Beed blasting fenders

[stan's52]

I am considering having my fenders, beed blasted to bare metal. I want prime them right after this done. What is the better primer to use? Catelized, or straight enimal primer (if still available) Thanks stan

[Plymouthy Adams]

will your blaster be doing this at a lower pressure and sand feed rate so as not to warp or heat the panels..most commercial blasters use high feed high pressure as it gets it doen quick..just a caution is all..as I have no knowledge of his process..I usually prep my blasted metal afterwards with phosphoric acid. a wash bath picking process that will treat any microscopic pores of rust not visible to the eye but yet present on the metal..after that..the primer of your choice..anything less than an epoxy primer will not seal the metal but only condition it and provide a substrate for the topcoats...do protect it from the elements..

[chopt50wgn]

You can chemical strip them and save yourself the cost and maybe warping. Then I always use an epoxy based primer. It will provide good protection and will accept doing bodywork over it as well.

[Plymouthy Adams]

the home DIY guy should never have a problem at warping the panels as he will reduce the pressure and use moderate sand flow...the commercial guys usually are flat out..now guys who blast wooden signs often use lower pressure..its all in the pressure and feed..and of course not staying in one spot..got a difficult area..hit it lightly let cool and come back..hit again, let cool and come back..never a need to hurry..I have blasted hoods, roofs, doors, trunk panels, the whole car actually with no problems whatsoever using my 40 lb pressure pot and keeping my pressure and sand flow in check..control all sand from the bottom of the pot..reduces line sand charge and waste when shutting down blasting..

[stan's52]

My compressor will not hold up with the demands of doing large items. I barley get my motorcycle parts done. The place I was thinking of blasting my parts, is a classic car repair shop. Most all they do is auto parts. It's just the finish I am concearned about. Stan

[Plymouthy Adams]

if you having it consigned to a professional shop I believe they also do the priming as it needs be done quick quickly after the process...but again..I would never prime without acid etching..ask the shop what their process is? If you do not have pressure to blast. I would say you would be borderline spraying HVLP

[falconvan]

Id have to agree with Tim; shoot them with a couple of coats of etching primer if you're starting with bare metal. Then I like either three coats of high build primer or there is a new product out called Slicksand that is a high build sprayable body filler. This stuff is great for blocking and really makes for some really smooth, straight panels after blocking.

[chopt50wgn]

To be honest............if you have a bare metal part that was bead blasted, there is no need to put etch on it. It is already been etched by the blasting. All you need to do is wipe it down with a pre-cleaner to remove any residue and apply epoxy primer. Epoxy primer will seal the metal and also allow for bodywork to bond to it.

The Slick Sand can be applied over the epoxy to do your blocking....but any blocking over Slick sand MUST be done dry. The SS is porous and will trap moisture under it. You must also topcoat the SS with epoxy after blocking.

I just got done doing all this on my wagon and got the whole education from a good friend who has a custom paint shop here in my area and uses all the products talked about.

[Plymouthy Adams]

I agree with the fact that blasting will give you the 'bite' needed for the paint and also the fact that the expoxy will seal..but I still apply a neutralizing acid bath, especially if the panels weere heavily rusted.....On the times in the past when I had used epoxy primer...I found busting this substrate's glaze for a proper bite for future primer surfacer just too much work..

[austinsailor]

Just shoot your sanding primer, or whatever the next coat is, over the epoxy within about 24 hours and no sanding is needed.

[Plymouthy Adams]

for me, any paint that has flashed on the surface will never be coated without being prepped..but..that is just me..

[austinsailor]

You need to check the manufacturer's instructions, but many, if not most, can be coated within a certain time and will chemically bond.

[Plymouthy Adams]

and that is why you never see clear coat coming off a new car...sorry..but that is a proven fact that contrary to manuf. specs and recommendations..it can and will still go awry and trust me..the time between the base and clear was not that great but enough to cause problems..and I am not a production shop that I need to turn quick products for to pay overhead and salaries so the extra minute to bust a glaze is nothing to me..most folks over the course of time will settle into a product line and a MO that they like to work with and that is the case here..I am not even sure they make the product I used long ago..I think it was Ditzler DP-40 epoxy..and I also had to spray the primer and then do a 30 days stint in the middle east..was pressed as it was to get it protected before shutting up the shop and hitting the road