Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 11-04-2019, 05:33 AM   #1
Steve Plucker
Senior Member
 
Steve Plucker's Avatar
 
Join Date: May 2010
Location: Walla Walla, Washington USA
Posts: 5,539
Default Sandblasting sheet metal parts

At what air presure should I have to sandblast some sheetmetal parts such as a radiator shell so as not to get any warping of the sheetmetal parts themselves?

Thanks.

Pluck
__________________
www.plucks329s.org

Walla Walla (WA) Sweet A's since 1993

MARC/MAFCA member since 1978

Ford Model AA Truck Club since 1998

(LIONEL/MTH Toy Train Collector, Orange Crush Soda Collector, Steel Beer Can Collector, Old Gas Pump Collector)
Steve Plucker is offline   Reply With Quote
Old 11-04-2019, 08:05 AM   #2
77Birdman
Senior Member
 
Join Date: Nov 2018
Location: North Eastern MD
Posts: 199
Default Re: Sandblasting sheet metal parts

I guess air pressure may have something to do with warping but heat created in the blasting process is what causes damage. As long as you do it gingerly you should not have a problem. If the surface is delicate you may want to use walnut shells. I typically use black diamond that i get at TSC, but it leaves a pretty rough finish.
77Birdman is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 11-04-2019, 08:15 AM   #3
Tinbasher
Senior Member
 
Tinbasher's Avatar
 
Join Date: May 2010
Location: Innisfil, Ontario Canada
Posts: 974
Default Re: Sandblasting sheet metal parts

The first step is to strip any paint that is on the Sheet metal. Then sandblast the part. Most of the time I use 90 PSI. and regulate the blasting by the distance I keep the nozzle from the work. If the part is really delicate I'll keep back 12". Normally about 6" from the work and just go lightly back and forth and up and down many times until it's clean. Go easy and take your time and you end up spending less time do metal repairs. Paint stripper is made to remove paint. Sandblasting is for removing rust. the two should never meet.!! Paint has great adhesion to the surface that's why people warp the panels as it creates so much heat by the time the paint is sandblasted off the metal.
Hope this helps. "The Old Tinbasher"
Tinbasher is offline   Reply With Quote
Old 11-04-2019, 08:46 AM   #4
eagle
Senior Member
 
eagle's Avatar
 
Join Date: Aug 2011
Location: Eagle Bend, MN
Posts: 1,507
Default Re: Sandblasting sheet metal parts

Also keep the nozzle at an angle to the metal, not straght on. If it is a thinner piece, ive dropped the pressure all the way down to 40psi. Nothing truly gets rid of rust in the pores like blasting, in my opinion. For fine work I use glass beads.
__________________
"There are some that can destroy an anvil with a teaspoon and shouldn't be allowed to touch anything resembling a tool."
eagle is offline   Reply With Quote
Old 11-04-2019, 08:48 AM   #5
chrs1961815
Senior Member
 
chrs1961815's Avatar
 
Join Date: Jul 2018
Location: Spring Grove, Illinois
Posts: 509
Default Re: Sandblasting sheet metal parts

I have blasted a lot of sheet metal with my outdoor blaster over the years and the method I use is a lower pressure and a going on an angle from further away if that makes sense. Basically shoot the sand from a 45 degree angle rather than a 90 degree angle.
__________________
"The more things change, the more they stay the same."
chrs1961815 is offline   Reply With Quote
Old 11-04-2019, 08:56 AM   #6
Oldbluoval
Senior Member
 
Oldbluoval's Avatar
 
Join Date: Jun 2015
Location: Signal Mtn, TN (SE TN)
Posts: 686
Default Re: Sandblasting sheet metal parts

Great advice from posts above. I’m not too fond of black diamond but other sands have gotten so expensive. Anything silica has been banned I think
Not heard good about soda blasting and may not apply to standard blasting system...not sure
Big thing is keep the sand pattern moving and don’t dwell on a spot as that’s where the heat builds up
Oldbluoval is online now   Reply With Quote
Old 11-04-2019, 09:12 AM   #7
Kurt in NJ
Senior Member
 
Kurt in NJ's Avatar
 
Join Date: May 2010
Location: on the Littlefield
Posts: 4,871
Default Re: Sandblasting sheet metal parts

I never had problems running the compresser at 45 lbs pressure for tin, I use a smiths compresser, set the governer to regulate max pressure with large enough nozzle----- the nozzles from the "weak"electric compresser when they get worn move I move them up the line, I have a water tank with a 100 foot coil for moisture condenser and then to 10 gallon water separator-- wet air goes in the middle, dry air out top, water leaking out drain valve( bad valve that never totally shuts off so the drainage is automatic, all connected with 25 foot hoses so compresser is upwind
I use a tip turbine compresser to inside the hood, gives positive pressure to keep most dust out, on hot days the hose gets coiled in a tub of ice water to be a crude form of air conditioning

I keep the bead blast cabinet at 45 too, the glass beads last longer before turning into dust
Kurt in NJ is offline   Reply With Quote
Old 11-04-2019, 10:13 AM   #8
marko39
Senior Member
 
Join Date: Oct 2016
Location: harpursville ny
Posts: 293
Default Re: Sandblasting sheet metal parts

I have found that blasting is expensive and messy. I blast but don't dwell on it, just get the heavy rust off and then spray with muratic acid which makes the rest disappear. Then neutralize with a solution of baking soda and water. Let it dry and you are ready to prime. Be careful using muratic acid as it is nasty stuff. A good wiff and you won't have to trim your nose hairs for a while.
marko39 is offline   Reply With Quote
Old 11-04-2019, 01:50 PM   #9
nick c
Senior Member
 
Join Date: Aug 2010
Posts: 224
Default Re: Sandblasting sheet metal parts

When I restored my 29 AA, I completely dismantled every piece of cab and running gear, sandblasted, 2k primer and urethane painted then reassembled it. My compressor is JD diesel, 125 cfm and 100 psi. I regulated it down to 60 psi, backed of 12 to 18" at a 45* angle. Some industrial suppliers only carry one size sand like 20/30, that's too course, I use a fine sand that looks the same size as common table salt, I buy in bulk 4000 lb. All my porcelain tip are 3/16" diameter, when they're wore out to 1/4", it reduce the pressure and spreads out the sand. You wont have any problem with pieces like the radiator shell, the problems come with the hood and door skin, do these last. I did the doors in side and out but did not spend much time on them, this is called dusting, I did not have any problems. I don't think the metal stretches because of heat, take a chipping hammer and put a needle point on it and strike the metal a thousand times, its the impact not the heat.
carry on

Last edited by nick c; 11-04-2019 at 06:39 PM. Reason: more info
nick c is offline   Reply With Quote
Old 11-04-2019, 02:52 PM   #10
Mad Mac
Senior Member
 
Join Date: Mar 2013
Location: New Zealand
Posts: 279
Default Re: Sandblasting sheet metal parts

After using a paint-stripper, use feed-grade molasses. It works well as a rust-remover and is guaranteed not to warp anything. Use a 6:1 mixture (water:molasses) strength and submerge for 10 days. You won't be disappointed.
Mad Mac is offline   Reply With Quote
Old 11-05-2019, 05:04 AM   #11
old31
Senior Member
 
Join Date: Jan 2016
Posts: 1,021
Default Re: Sandblasting sheet metal parts

Quote:
Originally Posted by Kurt in NJ View Post
I never had problems running the compresser at 45 lbs pressure for tin, I use a smiths compresser, set the governer to regulate max pressure with large enough nozzle----- the nozzles from the "weak"electric compresser when they get worn move I move them up the line, I have a water tank with a 100 foot coil for moisture condenser and then to 10 gallon water separator-- wet air goes in the middle, dry air out top, water leaking out drain valve( bad valve that never totally shuts off so the drainage is automatic, all connected with 25 foot hoses so compresser is upwind
I use a tip turbine compresser to inside the hood, gives positive pressure to keep most dust out, on hot days the hose gets coiled in a tub of ice water to be a crude form of air conditioning

I keep the bead blast cabinet at 45 too, the glass beads last longer before turning into dust
Kurt do you have any pics of your set up. Sounds interesting.
old31 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 06:26 PM.