next step after sand blasting skid

   / next step after sand blasting skid #1  

jingle135

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Joined
Sep 26, 2011
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10
Tractor
MF135
im getting my MF135 sandblasted tomorrow now that its all stripped down. i just want to check a few things.

1) After sandblasting do i need to wipe the metal skid down with anything. a cloth with chemicals?? or do i just air hose all the sand off and start with priming.

2) im using zinc phosphate primer, if i apply using a brush, will i get a good finish if a spray over it with the top coat?

thanks
 
   / next step after sand blasting skid #2  
jingle135,
I used to paint semis for a living. There's nothing better then sand blasting before painting. I prefer an epoxy primer but your zinc rich primer will probably be OK. Just make sure what ever you plan to paint over it is compatible.
regarding any treatment before painting, if the metal is freshly blasted and dry, then just blow it off with clean dry air and a rag then prime immediately. NEVER use acid on clean sandblasted steel because you will never get the microscopic rust out of the small pores. If you paint over microscopic rust, that's the beginning of the end. I wouldn't even wipe it with a solvent (prepsol, 3812, DX330) because you should not have to remove any oils from the surface. It is as clean and abraded as it can ever get once it is blasted. If someone blasts it for you and you have to bring it home and it starts to get any rust forming, then you might as well sand the whole thing down at that point. Ideally, the steel would be primed with in an hour of being blasted. Once it's primed, then you can sand and use body filler and primer surfacer etc. . . .
Remember there is a big difference between primer and sealer.
As far as if you prime it with a brush then spray the top coat, yea, the brush strokes will show. It all depends on how much time you want to spend and how much money you want to spend and what you want the end results to be.
Hope this helps a little :)
 
   / next step after sand blasting skid
  • Thread Starter
#3  
it helps a lot so thank you for your reply. i have a mobile sand blaster who is blasting the tractor in my yard. i intend on spraying it within an hour to prevent any rust forming.

im tempted to switch primers first thing in the morning tho. i was recomended zinc primer but it has to be hand painted and i dont like the idea. especially as i have a spray gun and a good compressor. i cant see how hand painting the wheels would look any good even if i were to spay the top coat over it.

i'll look for a epoxy primer tomorrow, is that better than a etch primer?
 
   / next step after sand blasting skid #4  
I use a bare metal treatment that contains phosphoric acid to convert the surface to a more rust resistant iron phosphate.



You can however just air off and use the zinc primer. Rumor has it that you can in fact reduce them with about 2x higher than the label directions and get excellent results with a spray gun. Rumor also has it that you would want to use a "fast" reducer so it won't run and to spray 2 light cover coats to get everything nice.

I have a HF paint can shaker (works very nice) and rumor has it that after 5 min of shaking the thinner primer is mixed perfectly.
 
   / next step after sand blasting skid #5  
Jingle135,
I don't know what end result your looking for to really recommend too much. Like I said, the zinc rich primer is probably fine. I just have a preference for epoxy primer. I'm a big fan of PPG products and love their DPLF90 epoxy primer but, it's not cheap by any stretch of the imagination. I've also used Kustom DTM epoxy (direct to metal) with good results. If you went to an automotive paint store, I'm sure they have several options based on your price range.
I've tried out the paints at Tractor Supply also and it's not too bad with the hardener added. Paint gets very expensive very fast. Try not to skimp too much. I painted an old MT372D Mitsubishi about 15 years ago, sand blast, epoxy, topcoat and it still looks great today, but that's when I owned a body shop and didn't really have to "buy" paint, I used what we had.
 
   / next step after sand blasting skid
  • Thread Starter
#6  
im shattered! Got the skid sandblasted this morning, i ended up using zinc phosphate primer. i spoke to a chap from my local massey ferguson dealer who is doing the body pannels for my tractor. he restores vintage tractors and enters them in comps so i trust his opinion.

i managed to find a zinc primer that was suited to a spray gun and the job looks to be coming on well. i've given 2 coates to the skid and parts.

i had planned on painting the top coats today but ive run out of time. Can i paint the top coats in a few days? will this be ok? will i need to use anything to get the paint to stick to the primer?

and finally.. i have a few small imperfections in the paint ie some dust as i was painting in my garage. im i ok to light sand before my top coats of paint?

big thanks again.
 
   / next step after sand blasting skid #7  
I don't know what brand primer you used and what they recommended as far as a time frame. Usually if you top coat with in 24-48 hours your OK. Some recommend that you lightly scuff after 24-48 hrs. Personally, I really wouldn't worry too much about it. I would probably sand out the dirt you have, lightly scuff the rest, blow it off, wipe it down with a prepsol (now that you've touched it with skin oils), tack it off and spray the top coats. Let it dry thoroughly before reassembling anything (a few days is best).
I hope you have a camera so everyone can what your accomplishing.
Don't rush it. Do what you can the best you can and it'll be fine !!
 
 
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