I know what there is to know about sandblasting........so just ask........garnet costs a fortune ,tho.,and a trailer is a time consuming thing to blast ....................depending on how much you want to do,how big the compressor is ,nozzle size ,etc...........Ideal size would be 300-370cfm at 125psi,3/8 nozzle ,and big Clemco pot(600lb)......to blast the whole thing to say, not quite white metal,all over ,I reckon about 3 hrs and 300lb of garnet.....or you could give it a whip over in probably 1 1/2 hrs ,and half the garnet.....you will definitely need a big water trap in the air line.......and a helper would be handy,to work the pot.
I had some wet sand blasting done today on our tractor. He used a coarse glass looking abrassive for the cast iron bits an d use a finer glass abrassive on the tin ware. I will put some pics in my thread in the tractor section under wet sand blasting tomorrow. Total time taken to do the tractor was 3 hours, used 8 25kg bags of abrasive and about 200 ltrs of water with a product in it to seter surface rust.
Where I was working ,they could blast a 40 ft container ,inside and out ,in 1 hour.........but that was two men,two nozzles ,cranes to turn over,and unlimited air thru 1/2 nozzles....over 1000hp in electric compressors.
Thanks John K, I'm not intending to set sandblasting speed records.
Just after an idea on what it might cost to do it myself as opposed to getting the yard down the road to do it.
Consideration needs to be taken, in that I have never done this before, but I see myself as quite handy & have seen it done.
The equipment I have not seen, but was informed that it was used extensively on this type of project before with no problems.
I would possibly take 2 to 3 times longer to get the job done than if it were you so if I work on doing smaller sections at a time & then etch priming these sections as I go, i should be able to get it done over several weekends.
If I take your estimate of 300lb of media & then double it to 600lb it kinda converts to about 280kg of blasting material.
Now flea bay offers bags of material for 25kg for $25.00 but if I double that it works out at $2.00 a kilo.
280 x $2.00 = $560.00 for media regardless on the type. A bit of diesel for tractor & supplying mates endless beers.
Cheaper than the quote I got down the road by a long way & possibly a new experience.
What do you think.
There shouldnt be any grease or oil to cause problems on a trailer....so it should be straightforward.....if someone can show you how much grit to use,OK,but most beginners use way too much grit,and create way too much dust.And waste garnet.........the nozzle should have a blueish cone of air and grit,and it should whistle....no whistle ,likely too much grit.Adjust the grit down until its just blasting at the speed you want.......then its just like reverse spraypainting........A good water trap is the key to trouble free ,and you also need a good pot boy.,to clear waterblocks without wasting grit.......and make sure the sieve is on the top of the pot.never put anything in that doesnt go thru the sieve......And wear the helmet and breathing gear,even tho its a major nuisance.......and you wont end up with spots on your lungs......consolidations the radiologist calls them.
Yes, the professional indoor sand blasters recycle their grit but have to pass it through a sieve to get out the old paint, dirt etc.
Depending on the medium it loses effectiveness because the grains get pulverized and lose their sharp edges. Some materials can only be used once because they get too smashed up and become too fine and powdery.
The standard ilmenite black stuff is usually good for a few runs if it is cleaned with a fine screen before each reuse. it is good to screen because ilmenite runs like water when it is dry. A big advantage is ilmenite creates comparatively little dust. Most of the dust you see is the rust off the steel being blasted, not the ilmenite.
We used to recycle ilmenite when sandblasting steel piles but it was marginal by the time you shoveled it up, screened it and made sure it was absolutely dry.
Garnet is widely used now and is recyclable also something called enviro-glass. Don't know what this is but it is not a good idea to use beach sand (although I have done it often when stuck for material). The "enviro" bit in the name would seem to indicate you will not get silicosis like you are in danger of using beach sand.
I fail to see how crushed glass can be OK ,but sand not.....glass is 7/8 silica,so how is it OK.......If you want to collect the garnet,just get some cheap blue tarps and lay them under the trailer.Ilmenite is problematic unless you are in Qld ,because its so heavy......something like 4 ton/cu m........so its dear to transport..................remember one thing,if the enviropolice catch you dry blasting with sand,you are in lots of trouble.
Enviro-Grit "Crushed Glass" Abrasives
Enviro-Grit Abrasives are made from recycled glass. This product is crystalline Silica-Free and contains no ingredients which are harmful to the environment. Enviro-Grit Abrasives are inert, non-flammable, non-corrosive, and non-fribrogenic.
• Provides superior cutting power for removing rust and most coatings
• Excellent for use on steel, aluminum, concrete, or wood
• Gives you more product per pound due to lower bulk density
I recycle the media in my cabinet blaster and besides all the advice given I would add that you need to get the dust out of the returned supply as it is the dust that stops things flowing in my experience.