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Sarge

Sand blasting tips and tricks

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WHX??

Thanks for the tips Sarge and taking the time to write up! :handgestures-thumbupright:

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pacer

Great stuff Sarge!! Am especially glad to see your stressing the need for CFM from your compressor. Sooo often you'll see "well my compressor puts out 125-135-150 etc PSI."  and while you do need a good pressure, it wont do much good if it runs out!

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Texas Todd

I have always used play sand outdoors (sifting it is a pain, but its cheap and washes into the soil) and clean bite glass media in my cabinet. I assumed the black diamond would make a real mess outside unless I tarped it. What is your experience? It doesn't look messy under that trailer, but it looks like it is washed in.

 

Also curious in how it compares to sand and glass in function? I only have sand and the glass experience, so the black diamond may be worth trying next time.

Excellent write up!

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squonk
3 hours ago, Texas Todd said:

I have always used play sand outdoors (sifting it is a pain, but its cheap and washes into the soil) and clean bite glass media in my cabinet. I assumed the black diamond would make a real mess outside unless I tarped it. What is your experience? It doesn't look messy under that trailer, but it looks like it is washed in.

 

Also curious in how it compares to sand and glass in function? I only have sand and the glass experience, so the black diamond may be worth trying next time.

Excellent write up!

play sand has way too much moisture in it that can cause clogging of the unit. And if you leave it in a pot blaster, well you'll have a mess. 

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pacer

Play sand---- Totally aside from the fact that it is EXTREMELY dangerous, causing Silicosis? sp with relatively little use and that along with squonks mention of moisture is the irregularity of the media, to often a larger pebble will come down the pipe causing a blockage that being somewhat moist is the very devil to get unplugged. Yes, Black Beauty, or similar, is sooo much better. As far as making a mess, I dont think so, I have probably 50-60 bags scattered just outside my shop in a somewhat grassy area and after a few rains and some grass growth its hardly noticeable.

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oliver2-44

I use red garnet in my cabinet. It mor expensive than Black Beaty but last a lot longer and makes less dust. 

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Texas Todd

I will have to get it a try. I have sifted the sand (very dry sand) and used it with a bucket/siphon. But again, have nothing to compare it to. Always use a respirator. Assume you would want to use a respirator with any of the medias. I use the respirator with the cabinet as well, as it a HF benchtop and isn't the most well-sealed unit.

So Black Beauty outside and red garnet inside. Will give both a shot.

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Sarge

No type of silicate should ever be used for blasting . Now , that said I have used it in the past quite a lot and it does work well - we have 4 very large pits near this area so the stuff is pretty cheap . Using any type of silicate requires the use of a respirator and honestly you need organic rated cartridges to really be safe - the normal R100 series dust filters are not good enough . I've watched several of our Retirees die a slow death from silicosis - no human should ever die that way but years ago they didn't use any sort of protection from the stuff - just didn't know any better . Due to all the training we have to carry and certifications to work in my industry (Union Laborer) I have the equipment here to prevent problems - but that equipment is seriously expensive . Last set of cartridges I bought were nearly $100 alone - those are just for painting with enamel hardener and reducers . Having full HazMat , IMSHA , OSHA certifications keeps us up on industry changes and requirements for protection , not to mention being educated on what can slowly or quickly kill you .

 

Now , as to what the average guy can use in a blast pot , safely -

 

Be careful buying coal slag - it's cheap on average but will contain traces of silicates . Quality brands will be lower amounts but it's always there - so wear protection . Do not rely on cheap dust masks - they will not protect you from lead or organics in existing paints - remember the age of our tractors and some related equipment - even trailers . Older paints can contain lead and several other bad elements - so when you blast it the stuff becomes airborne in small enough particles to be ingested into your lungs/sinus systems . Same with zinc based galvanizing compounds which can be even worse . Wear a respirator and read up or get training on proper and correct mask fitting from a local Fire Dept - they can show you in short order the proper fitment of a half mask . There are times you can't wear a blast hood - when using a grinding shield or similar a lot more particles end up in your face , so proper fitment is very important or you're wasting your time . Ear plugs are also a must - the noise alone is bad enough but getting that fine dust in your ears is not fun , nor easy to flush out and can cause infections , been there - done that on a big pipeline project .

 

As an example of grit size / dust content and results -

Black Diamond from TSC in coarse grade , very little fines (dust) versus the Black Blast from Menards - around a buck a bag difference in price per 50lb bags .

 

59a9523bb250d_20170831_1859211.jpg.035c80c306c127538bb6ebf23eaa3182.jpg

 

59a952bcbe60f_20170831_1408051.jpg.8f63e3b22cec8ef56d00672b20f50b3e.jpg

 

The excessive dust in the Black Blast from Menards means it will not cut nearly as efficient , especially on heavy mill scale and rust - nor cut through heavy paint runs as is the case with many trailers . Not to mention it takes forever to get any decent results . Keep in mind that the more coarse the media , the larger the nozzle size required to use it - the coarse Black Diamond at that heavy grit range takes a 5/32" tip size at minimum . Testing last night after waiting all day for UPS to show up (they are usually here by 10:30 , but didn't come until 16:10 !!) wasted a whole work day in perfect weather , but the new nozzles at that size work excellent and don't run the compressor out of the cfm needed to make the pot work correctly . The lighter media from Menards can use 1/8" or even smaller nozzles , but will not do the heavy work such as this extremely thick , rusty mill scale that they painted over -

 

59a9530471210_20170831_1408431.jpg.389f381c1572f0004589bee576e1923d.jpg

 

59a955b7a47ad_20170831_1405301.jpg.460ede0299a9d3c399d0a489427ea176.jpg

 

I'll try to get some pics later today to show the results of the heavier grit media from TSC - it works 3 times as fast and cuts right through that scale in a hurry , far better results and much less overall dust . It's nearly impossible to photograph the detail in the metal , but I do not recommend this heavier media for use on thinner sheet metal - you'll have to fill in the surface with a lot of builder/primer to get a decent finish job on your paint . On really thin metal it could actually cut through or even warp it from heat - yes metal can get hot from the abrasive action of the media .

 

Here's the mods to the Clarke pot setup - first is the modified feed piping and the wye fitting to aid in better flow mixture of the media into the air stream -

 

59a953d079eac_20170831_1403341.jpg.6f3153101dbb6e4554149d3a7e8b0433.jpg

 

3/8"x1/4"NPT "T" style high flow plug fitting to get better cfm through the pot system -

 

59a95395c068b_20170831_1404231.jpg.411c07e37ad31ef77fe75a5256448c2e.jpg

 

The older style water separators flow better than the newer ones - you may need to upgrade the separator if you have a newer pot or one of the off branded ones . Most of the culprit is the moisture wicking coalescent element inside - they are too fine to allow enough cfm to flow through and plug up easily . High cfm rating separators can be had in 1/2-3/4NPT sizes pretty reasonable - just make sure parts can be had later .

 

The business end of the blast hose setup -

 

59a953b11e0cf_20170831_1403531.jpg.d53433c2b8cff6949d0c83390d787a74.jpg

 

This is not a dead man valve setup - so be aware if you happen to lose control of this thing it can seriously hurt you - sandblasting streams will remove clothing and skin very quickly and the results are not fun to look at . This setup is just a simple hose adapter , 1/2"NPTx3/4"NPT adapter, 3/4" steel ball valve and the nozzle adapter sold by the auction site seller . The nozzle is the common C series 3-3/4"L X 1-1/8" base diameter and 5/8" tip diameter tapered cone nozzle style . These are high velocity venturi style nozzles , hence the tapered portion which will accelerate the air volume/pressure and concentrate the media into a blast stream . Far more efficient than the usual straight nose wide pattern or short nose style nozzles sold with many of these blast pots . The last 1/8" nozzle ran through 1,100lbs of finer media before any noticeable change in tip sizing - it's out to .138" compared to the starting point of .125" (1/8") . Very little wear versus how much work it's done already and lots of life left . The new nozzles I buy are now from McMaster and are ultra hardened ceramic USA made quality nozzles - around $11.42 each and will outlast any of the small nozzles 10:1 easily . McMaster does sell the real-deal dead man valve setup for use with these nozzles - it's right at $100 and probably worth the investment just for safety's sake . They also sell the rubber stop blocks for that valve setup at a minor cost for 3-packs . This stuff , while expensive will put a cheap blast pot nearly on par with commercial equipment , albeit a couple thousand dollars cheaper . The whole key to doing this stuff is having an air compressor that can handle the task and push enough cfm to do the job .

 

It's also very important to note I'm running large diameter piping , hoses and fittings . At the smallest point I use 1/4" I/M plugs and couplers for most small air tools and such by running an adapter to go from the larger high-flow 3/8" "T" style plugs/couplers . The smallest hose I run on anything in the system is 3/8" . Piping system is 3/4" and the main hoses are 1/2" with 3/8"NPT ends , not the common 1/4" hose ends . This makes a huge difference in flow and heat back to the compressor source and keeps the cfm high enough to do this type of work . I'm also using a second 60 gallon reservoir tank outside to aid in storage to take some loading off the pump . Biggest trick is trying to keep the water out when it's humid and lately that's been a real issue . The pipe leg drops in the basement catch a lot of it and 3 different system filters along the way help as the air stream cools from the distance traveled to the blast area . A proper chiller and air/water separator would be the ultimate setup but even smaller systems cost several thousand dollars . If you're really serious about doing larger jobs it would be much better to rent a trailer mounted rotary pump setup at least 85cfm in size - then you'd have unlimited air flow for an even larger blast pot system . I missed out on a nice 85cfm trailer unit last year - it sold for only $800 due to the engine not running , which I can fix easily enough . I'd really rather not do large jobs anyway - so no big loss there .

If I were younger I'd be very interested in buying into a full trailer mounted dustless blast system - but not at my age , lol .

 

Red garnet cuts great , but in cabinets it's really tough to keep up with the dust and have a large enough dust collector that can handle enough air flow to keep the cabinet cleared . The Scat HEPA blast collector would work well , but they are around $400 for a decent sized one . Just a heads up too - shop vacs aren't a good idea for dust removal - their motors and filters are not rated to handle this type of dust and will basically spew a lot of the most harmful small particles into the air around that vac . Yes , using a respirator when even doing cabinet work is a good idea - no cabinet system is perfectly sealed unless it's a dedicated commercial cabinet with a matching dust collector and protection must still be used when servicing the system . An alternative to garnet , which is expensive for what it is would be to use angular shaped glass - it will remove the heaviest rust scale and paint and still leave an acceptable surface finish for painting . I generally run 40/80 glass beads in my big shop cabinet with good results and it's cost isn't bad .

 

I'd never recommend using play sand - it contains a certain percentage of clay - that is what will bind it together and it also attracts moisture like a sponge . If you want to keep costs down , use a very fine coal slag and a small cone nozzle setup or Scat's trigger type blast gun for siphon systems and a large, clean tarp . The material can be re-used and screened to remove dirt and recycled . Be aware that this will create more potentially harmful dust since you're adding in paint dust , rust , galvanizing/zinc coatings and such, so again - respirator is a must .

 

One other thing I have not touched upon but it's important in both cabinets as well as outdoor siphon/pot blasting - pressures . At most I run 100psi of air pressure , regulated at the compressor's outlet by a filter/regulator . Using excessive pressure over 90psi will quickly erode gun parts , blast hoses and in cabinet systems it will destroy the media much quicker . If you're not getting good results it's a lack of cfm and velocity in your system , not a lack of pressure . On large commercial pot systems we use at Work we only run 90psi on everything - it's the industry limit . Results come easier the more cfm used and the better the nozzle design - hence my upgrading the pot system as well as my cabinet to better nozzles . The Scat blast gun in the cabinet (more pics to come) uses a tungsten carbide nozzle that is designed to provide a much better wear rate and keep the stream shaped correctly . On that type of blast guns it's also important to have the correct air jet and they still wear and have to be changed . Cheap siphon guns sold for bucket use have their air jet built into the handle so once they wear much the gun is useless . Once the air jet is worn you'll also wear out tips faster - so keep that in mind too .

 

One of these Scat 35 series guns , a suction hose and mixer and a bucket for media with a decent compressor could get you started and provide much better results than the crap Campbell setup at home and farm stores

http://www.tptools.com/S-35-Series-Trigger-Operated-Power-Gun,8592.html?b=d*8026

http://www.tptools.com/Siphon-Hose-and-Pickup-Tubes.html

Replacement nozzles and air jets are cheap and you can size them to fit your air system's cfm capability easily with some research .

 

Anyway , hands are tired and I've got to get out there and get to work - more pics/info to come...

 

Sarge

 

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Texas Todd

Great info Sarge! :handgestures-thumbupright:

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pacer

Sarge is really getting blasting business covered!!

 

He has mentioned the need for a means for reducing/removing dust from the blast cabinet, this is almost a MUST - dust quickly clouds up the view in the cabinet and if you cant see your part its pretty difficult to get it clean! He mentioned one recovery system and I thought I would point out another one, I have this one on the side of my cabinet and it does a heck of a job clearing the dust. And, the really good part is its really inexpensive - from our good friends at Harbor Freight ;) They call it a "reclaimer kit" but while it will reclaim the dust its far to fine for reuse (at least in my use

  https://www.harborfreight.com/blast-cabinet-reclaimer-kit-60739.html With one of the  

With one of their 20-25% coupons its only a little over a $100

image_21642.jpg.2fe400eeed46b50378552278d9d6e6b2.jpg

 

 

 

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Texas Todd

I have a 2 bucket system. The first bucket in the chain has some water in it and the vacuum comes from a homer vac on a second bucket. Works really well. Plenty of videos on you tube. It always amazes me how much dust "more like mortar" the first bucket captures. But it keep the chamber clear enough to work.

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Sarge

Yesterday turned out to be one very unproductive day . The "coarse" coal slag from TSC turned out to be sized badly - first bag was ok , second one wouldn't hardly flow through the bottom mixer valve and kept plugging up the nozzle with chunks of grit over 3/16" in size - measured one out at .232" , nearly 1/4" . Evidently , the company has some bad screens and just kept making media anyway , nice...

Took the last 3 bags back and exchanged it out for 5 bags of the finer grit . Not what I really wanted to run , prefer the 30-60 range but this will work being up to 80 range , albeit slowly on the heavier mill scale . Wife also had an appointment at the Doc and found out she had broken another toe - ran into the doofus Lab mix of ours and he's north of 110lbs....dog never moved or hardly woke up . So , that was two trips to the nearby town and a day wasted , again . That thing is getting primed today - clean or not as I'm done with working on it , should have scrapped the dumb thing in the first place . This time of year around here the weather can change fast - got several outdoor projects that need blasted and painted and I'm running out of time too quickly - I swear the old man upstairs doesn't want me to finish anything lately , nothing but delays and interruptions .

 

If I can't find a better , cleaner and more consistent coal slag mix I may just go back to using white silica - it's much cheaper and easier to get around here bulk . I use a half face respirator anyway and have dealt with the stuff for years at work , so it's not like I don't know what I'm doing . It's too bad none of the store chains carry a good consistent material , but I guess it's gotten like everything else in the retail business - all profit on crap products . The stuff I used to buy had almost no dust in it and was super consistent in screen size - none of the 5 types I've found around here are even close , enough to drive a guy nuts .

 

Next issue is fighting the red oxide primer and this odd weather - feels like an early Fall coming and temps today are almost too cold to spray it . Might try using some acetone to get it to flash off faster and gas out so I can get the color coat on either tomorrow or Monday morning - probably get called out to work by the middle of the week so it needs to get done . Going to use a heavy mix of hardener and high temp reducer on the top coat - hope it works out ok ....

 

I'll try at night to get some pics of the blast cabinet setup and it's gun system . Have been really impressed with the consistent results from the Scat gun and it's parts - lasted far longer than ever expected and these days that's rare for sure . Mine is still using an old cotton canvas bag system from when it was new and a small blower that clears the dust . It works ok , but the pores in the bag clog easily and it's a serious mess to clean it outside once it starts losing efficiency . Might visit using a cyclonic separator system like the Dust Deputy I use around the shop to clean up metal debris - that thing works excellent . The right separator and a 100cfm Hepa dust collector would sure go a long way in making the cabinet perform better and keep the shop cleaner - don't really need grit dust around the machinery .

 

Sarge

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Sarge

Went through another 400lbs of coal slag yesterday finishing up the main frame (some pretty nasty areas) and getting the 2 ramp sections done - that seemed to take forever due to the expanded metal . I'm about wore out and my lower back really took a beating yesterday . Last bag on the shed floor from the stack turned out to be wet as heck from being in contact with the floor - got it fed through the blaster without too much issue but it definitely doesn't cut as well as dry material .

 

59ac0bb8821ba_20170902_1900101.jpg.8881da9b74a51f18b40cb037593c56da.jpg

 

I tried getting some pics of the difference in anchor profile of the different grades of media - but the gray/silver color of the steel just doesn't let the camera see the surface detail enough with a filter or something . On the main frame , the difference is almost negligible - but it does show up on the sheet metal fenders a fair bit - maybe the primer will show it more clearly .

 

Now that the weather is changing yet again with more humidity - time to prime it and get it curing . Using Rustoleum's Rusty Metal Primer (red oxide) and I wouldn't be surprised if it takes until Wednesday before the top coat can go on it . Might try some acetone to reduce it a bit for running through the old Sharpe gun I have - at least then it has a better chance with this weather change .

 

When it's done , cured and back on the ground I'll have to get the gravel ripper out and work that coal slag into the parking lot - when the stuff gets wet it tracks inside easily and sort of turns into a nasty mud mixture...

 

Sarge

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pacer
1 hour ago, Sarge said:

when the stuff gets wet it tracks inside easily and sort of turns into a nasty mud mixture...

 

Boyoboy thats the TRUTH!! Stuff almost seems to have glue on it when wet! And my wifey sure doesnt like that.

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Sarge

I swear , that somehow the Old Man Upstairs is mad at me or something - every time I turn around it's something else going wrong . Started to prime the bottom side yesterday and noticed the air pressure dropping at the gun - compressor was not running . Tested the obvious stuff , breaker/air switch/starter box/relay/wiring and no luck - everything had power going through just fine . Spin the flywheel and see if the pump is locked , nope - spins just fine and the unloader is working fine . Get on the phone with an electrician buddy because the start/run capacitor box stinks - used the Phoenix meter he had recommend I get (love that thing) to test each one and yup , one is burned out . No stores this weekend carry them , so off to an electrical supplier to where another electrician/hvac buddy has an account to get me in the door tomorrow - they should have them in stock . Replacing all 3 since they are original to the motor , which is a huge , heavy bugger out of an old corn crib lift because the original motor on this thing was a 3ph and needed a single phase 5hp . Hope to have it back running by noon barring anything else that's wrong internally in the motor ....I just can't get this thing done .

 

Primer went on a bit too dry with the acetone - had to thin it down 10% to get it through the Sharpe gun but the stuff flashed off too fast so it's a bit rough . Will have to wet coat those areas again with hot reducer but it should be fine . Considered using an acid etch additive but can't find a drop of info on using it with Rustoleum and the stuff is touchy chemically so I'm leaving it out . Besides that - it's highly destructive to paint guns - the stuff ate the needle tip off the other gun and had to replace it after only 2qts of material so it's not a totally bad thing .

 

I needed a day off anyway , guess I won't complain but this thing is becoming a career .

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JPWH

The man upstairs isn't mad. Just showing you how much you can endure.:handgestures-thumbupright:

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