smoothing welds
- Thread starter Johnny
- Start date
putz
Member
Here is a previous posting on this grinding down welds can really weaken your welds especially if you are new at welding.
Smoothing welds link.
Use bondo just as would on the body of a car.
Wild Mango
Member
Bondo won't hack the temp. Be very careful when grinding the reinforcement off your welds. If the penetration is not very good due to the procedure or process you may be grinding away a lot of the strength. If I am going to vanity grind welds I make sure they have a good vee prep and the penetration is 100% - i.e. the weld fuses the whole setup gap.
Look at alvinproducts.com. I get it at the welding supply or at Fastenal(spelling).
Seems I recall we have a member who is very experienced in powder coating. He would be a better source of knowledge
I've been told by one powder coater that those epoxy based fillers may lift up at the feathered edges of the filled area during the trip through the oven. This assumes the filler wasn't removed during the sand blasting op.
To chrome plate over a welded area, I would cover with braze, then grind to blend and finish.
I've been told by one powder coater that those epoxy based fillers may lift up at the feathered edges of the filled area during the trip through the oven. This assumes the filler wasn't removed during the sand blasting op.
To chrome plate over a welded area, I would cover with braze, then grind to blend and finish.
When dressing welds for chrome I just remove enough to take of the high spots and ridges. The polishing will smooth out whats left.
I know folks like to have that smooth molded look but there's nothing wrong with a good looking weld painted, powder coated or plated.IMHO
Ron
I know folks like to have that smooth molded look but there's nothing wrong with a good looking weld painted, powder coated or plated.IMHO
Ron
I prefer the look of a good weld over a smoothed out one also.
chopfather
New Member
what bruce said :winkn:
Screaming Metal
Active Member
What Bruce and ChopFather said. If you weld it right, all you'll have to do is just some minor smoothing.
Grinding on top of the weld weakens it. If your not a experienced welder yet, don't go grinding on anything. If this is something your inexperienced at, get someone thats good at it and let him look over your shoulder and let him guide you.
A frame coming apart going down the road is a receipt for a whole lotta no fun!!! :winkn:
Grinding on top of the weld weakens it. If your not a experienced welder yet, don't go grinding on anything. If this is something your inexperienced at, get someone thats good at it and let him look over your shoulder and let him guide you.
A frame coming apart going down the road is a receipt for a whole lotta no fun!!! :winkn:
cozee
New Member
As has been mentioned, any removal of the weld should be minimal. Learning to make a good weld is this best.
Regular plastic filler (bondo) WILL NOT typically work for powder coating as the surface being powder coated needs to hold an electrical charge. I say typically as 1. plastic filler usually cannot take the heat ( which can cause problems during the bake or later on down the road. One is even taking a chance with a very thin coat. Weld joints can be covered with solder or a low temp brazing rod (I'd mention lead but not sure if the health police are reading this!!! LOL!!) then smoothed prior to powder coating or chroming. As for something to apply over welds to smooth them out for primer/paint, personally, I'd use Fiberal (modern day Tiger Hair). Sands very well and other than needing more shaping or to fill open air pockets, you can primer right over it. If one wants to use plastic filler, I suggest using Quantum. It costs a little more but you can apply it, come back 30 days later, and it sands very easily with 120-220, not like regular filler which turns to granite in less than an hour and needs a grinder to knock it down.
Regular plastic filler (bondo) WILL NOT typically work for powder coating as the surface being powder coated needs to hold an electrical charge. I say typically as 1. plastic filler usually cannot take the heat ( which can cause problems during the bake or later on down the road. One is even taking a chance with a very thin coat. Weld joints can be covered with solder or a low temp brazing rod (I'd mention lead but not sure if the health police are reading this!!! LOL!!) then smoothed prior to powder coating or chroming. As for something to apply over welds to smooth them out for primer/paint, personally, I'd use Fiberal (modern day Tiger Hair). Sands very well and other than needing more shaping or to fill open air pockets, you can primer right over it. If one wants to use plastic filler, I suggest using Quantum. It costs a little more but you can apply it, come back 30 days later, and it sands very easily with 120-220, not like regular filler which turns to granite in less than an hour and needs a grinder to knock it down.
Keeper
Active Member
I was asking the powder coater about using bondo and coating. He told me that you will most likely get bubbles wherever the bondo is. "If you want to smooth things, use a hard epoxy that plumbers use"
Now I have not looked up what epoxy that plumbers use yet, but might give you somewhere else to check.
Now I have not looked up what epoxy that plumbers use yet, but might give you somewhere else to check.
ruggs
Member
Keeper, I use a product called (ALL METAl) this is an aluminum/epoxy mix and works simular to body plastic. We have used it under powder coat on several frames and such but. do a sample piece first and have them powder and bake it. That is what I did but maybe your powder coater uses a higher temp, We bake at 400 degrees.......Ron (ruggs)
I've used all metal, and it works ok. they have several versions that handle from 350 degrees all the way up to 2000 degrees. I recomend you buy from a local supplier that knows you however, as the shelf life isn't very long. I've purchased product that was 1/2 hard and grainy in the can and had to return it.
my local supplier, BTW, was Fastenal. most outlets will have it.
.02
Russ
I was wrong. [first time today] the product I used under powder coating was called Lab Metal. it was purchased from Fastenal however. All metal and other similar products may also work, but I haven't used them myself. sorry. I had a brain fart.
Russ
ruggs
Member
Russ, Lab metal is probably close to the same product but, I really need to stress that anyone using either product needs to do a test first. I've never had a problem with bubbles or anything but I also use it sparingly....Ron (ruggs)
benT
Active Member
We've used Lab Metal some at our Powdercoating shop. Like Riggs says, use it sparingly. It is not like bondo where you can glob it on and "sculpt" it. It does work ok on filling pinholes and such. I definitely agree with Ruggs on the "do a test first" statement. The biggest issue we have in powdercoating is off-gassing of materials. We typically "burn-off" most items before blasting and coating, but some alloys off-gas more than others and can cause bubbles and flaws in the coating. We've had good luck with Lab Metal, but don't think we've used the All-Metal. Might have to try it out.
Of cours one could play devils advocate here and say that under the right conditions, grinding the welds smooth could actually strengthen them by eliminating stress risers.
Russ
Russ
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