4 replies to this topic

[Compdoc]

I took my subframes down to the soda blaster yesterday to leave them with him, prior to getting them powder coated. When I got there they'd all gone to lunch, so decided to shoot round to the powder coaters to keep him in the loop.

God job I did, because when he heard that I intended to get the subframes soda blasted he told me not to do it. He said that they had had problems before with powder coating not adhering correctly to steel previously soda blasted and suspected that the soda was so fine that it embedded itself into the surface. Plus they had to wash the part vigorously and dry it prior to powder coating and even then they were not happy with the coatings adhesion.

I thought that soda blasting was the best thing since sliced bread, but now I'm not so sure. I just wondered if anyone else on the forum had experienced anything similar.

 

 

[dean]

you get thing blasted in different way and with different abrasives for different things.

 

i always had mine sand blasted and powder coated, but they are done by the same company so all under one roof.

 

soda is good, much less heat so great on body work ,alloy parts  etc,  , but something solid like a subframe will be fine just to sand blast, it will come up cleaner as such and remove more for the rust/rot etc. but make sure you wear gloves when you pick it up ,not your bare hands. the metal will love the moisture in your hands will leave a mark, it has to be very clean to make sure the powder coat gets a good key to the metal.

 

does the blast company, hot zinc, or galvanise coating. at least you know you have good barrier under the powder coat

Edited by dean, 08 June 2016 - 08:42 AM.

[fwdracer]

Sand Blasting provides surface key for powder coat or primer. Soda - too fine, ideal on alloys. Personally I'd paint and 2K the subframes. When powder coat is broken, rust creeps under the surface. With Primer & 2K, the rust doesn't creep and it is easier to touch up. Just my opinion.

[Compdoc]

Hi, thanks for the advice. I've now caught up with the soda blaster and he agrees that soda wouldn't be suitable for powder coating. He suggested that sand blasting would leave a better surface. He also said that more aggressive blasting doesn't necessarily overheat and warp sheet metal, it all depends on how its done and the experience of the person doing it. As he was in the process of blasting a Mini shell that looked really good I think he knows his stuff. I wish now that I'd had the whole shell blasted before I spent a month scraping 40 years of multiple layers of underseal off the underside.

I must admit I do like the sound of "Hot Zinc" presumably dipped. I'll find out if the powder coater can do this.

[absx2]

+1 on 2K paint. We have wet and dry soda blasting at work as well as media ( aluminium oxide ) blasting and the biggest problem with any is no matter how much you blow it out of the various cavity's it finds itself in you can never get it all out. which always gives huge aggravation come finishing time. Its not so bad with vintage m/cycle frames as you can bung the holes up.

 

As for power coating I wouldn`t bother as the first time it gets a jack under it or you rub the edge fitting a shock its game over.

Power coating in my opinion is a poor product that has been given a load of hype by the people that tout the stuff. Its dirt cheap, needs no talent to apply it in a couple of minutes and is completely useless once the surface is damaged which is usually straight away. Quick and easy money.

 

Poly 2k primer has anti corrosives, is highly resistant to moisture, chemically etches into the surface and will not flake of peel. Add 2k black as a top coat you`re sorted forever.

Hot galvanizing would seem ideal if not for looks but there have been issues where thin gauge parts have come out bent so you would be looking at electro plating instead.

The serious 4x4 off road guys won`t use a galv chassis on their landrovers as they are more prone to cracking so that`s enough to knock it on the head for me.

 

The soda does indeed leave a few microns of plastic residue on panels actually prevents oxidation before prep and paint that is usually removed during final prep but certainly would not be by power coaters. 

Edited by absx2, 08 June 2016 - 02:38 PM.