Yes.
I am talking about BOTH painting and powdercoating.->
In production I have found that there is usually outgassing that will occur along these welds causing bubbling to occur as the coating is geling in the oven. The gas or expanded air will pierce the coating leaving marking, and penetration, pitting or rippling allowing future corrosion opportunities.
High temp bonding putty, don't remember the name~ made by Dupont, would adhere to properly cleaned surfaces- alum steel etc.- when dried and sanded and cleaned with automotive dust wipe
cloths and denatured alcohol, the powder would not show spoilage on the welding bead areas.
Powders have different gel temperatures and set times from seconds to almost a minute.
There are very expensive automotive gelcoats- wet primer that will work if the powder and pre coat are compatible.
You need a material that will not show heat shrinkage nor burning at high temps avg 350-450*f
The powders melt, flow, gel, then set. They are usually resin composits, with ingredients tailor made to cause certain timings in flow and finish.
There are metalic appearance combinations etc. Certain techniques are used to cause variations. In production heat dwell in the oven and timing are critical to have all parts in a color batch match the last batch. Variance is an issue between lots of powder also. Your powder supplier will usually be happy to help your coater learn specific techniques to acheive consistant results. If you need more specifics, Duponts website will supply info on each and every powder they make. I am not a fan of Dupont persay but they have better customer service help than most by my experience and they provide accurate data.
Each territory has a customer rep. they will be glad to visit on site for most powder purchases over $500.00.
Most platers and blasters have business relationships with powder coaters.
My advice, if the shop seems while not perfectly clean, at least clean and organised and clutter free
and they keep their powder in a cold dry storage place,
then they probably know what they are doing.
Guns and equipment must always be time-consumingly cleaned and maintained to prevent cross color contamination and poor application.
Dirty poorly organised mad scientist/ artist shops are to be avoided. Thats where crap is born and money lost. Not knocking artists but most have clean organised shops and will expect good money.
You want a cheap job, go to walmart and buy spray paint in cans. You want a good job, you will have to pay for it but ask how the price is figured out. A good shop will explain and detail their billing and remember if you pay for the powder upfront, which you may have to, you take the remainder home if you want it for later projects. Powder, stripping services, wash and pretreatment, labor, gas or electricity for ovens, line time and money for artistry...
Ten years ago a charge of 150-200$ for a frame and fork assy if they had come to us fresh from a blasting shop for a single color with 2 coat passes. 500$ was the most charged for a special color blend with mulitple (2-3)colors.
The powder was always charged
seperately to avoid disputes later.
Art work and specialty stuff needs to be negotiated.
Supply a simple pattern schetched out on paper- you are not their only customer and people forget sometimes what was said last week, you and the shop.
Small stuff is usually scheduled to run with similar colored jobs for others.
If the shop has a small batch oven, you might get a better price for small parts, mirror assys, handbrake handles, clutch pedals, fenders etc. If you are having the whole bike done ~do it all at once so the color and tone and finish match.
Once coated it is too late to fix with out more time and labor and money.
Blame yourself if you did not specify what you wanted.
Get a written receipt of the parts supplied and work to be done, that has a company name address and phone number.
Take photos of parts before sent so you can back yourself up if a dispute or problem occurs.
Know your coater,
he may become a lifelong friend,
and you may become a hero to the rest of your buddys for finding a good shop.
Ride hard, ride on.
Zep