ok guys another question for ya !! i see alot of guys talkin about etching primer, what r the do's and dont's, why's and why not's of this stuff never used it and need some info! do i only use it on bare metal ? is it at all possible make it look like u havent used bondo..ive filled sanded filled sanded primerd painted and u can still tell i used bondo ...i mean it looks good and flat till u add paint ...then it sticks out ..just keep sanding i guess ...or do u guys use something besides bondo ? trial and error ....? thnx
painting
- Thread starter mikesbikes36
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Go to the arts and crafts store
Buy some 1/4 inch thick balsa wood
cut a section about the size of a PEZ dispenser (or about 1/2" wide) and wrap it tightly with trimmed 220 or 320 wet/dry sand paper. Get a bowl. Fill it with water and totally saturate your paper. -Miniblock
To achieve a featherd edge, you MUST take your time. You must wait a long time for the hardener in the Bondo to fully kick.
Sand in mostly different angles of approach every 3 or 4 strokes and keep your paper wet.
You are just not taking your time.
I like ice cream.
Do you?
Chocolate is my favorite flavor. What's yours?
Blah blah blah.
Buy some 1/4 inch thick balsa wood
cut a section about the size of a PEZ dispenser (or about 1/2" wide) and wrap it tightly with trimmed 220 or 320 wet/dry sand paper. Get a bowl. Fill it with water and totally saturate your paper. -Miniblock
To achieve a featherd edge, you MUST take your time. You must wait a long time for the hardener in the Bondo to fully kick.
Sand in mostly different angles of approach every 3 or 4 strokes and keep your paper wet.
You are just not taking your time.
I like ice cream.
Do you?
Chocolate is my favorite flavor. What's yours?
Blah blah blah.
1 Apply bondo, after its cured, hit it with a coat of primer.
2 Sand with sanding block, when you get thru the primer to base metal around bondo, stop sanding.
3 Hit it with a coat of primer.
4 cover all the Bondo area and out past the edges with glazing filler, hit it with a coat of primer.
5 Do step 2 thru step 4 until when you shoot the primer, you can't see the filled area thru the primer.
6 Move on to full primer the part and paint.
Assumption is that you allow full cure of fillers and primers between steps. You are wet sanding with plenty of water. As you get the edges feathered out, be less and less aggressive with your sanding, use finer grits, and always use the sanding block.
Just my humble .02 cents.
2 Sand with sanding block, when you get thru the primer to base metal around bondo, stop sanding.
3 Hit it with a coat of primer.
4 cover all the Bondo area and out past the edges with glazing filler, hit it with a coat of primer.
5 Do step 2 thru step 4 until when you shoot the primer, you can't see the filled area thru the primer.
6 Move on to full primer the part and paint.
Assumption is that you allow full cure of fillers and primers between steps. You are wet sanding with plenty of water. As you get the edges feathered out, be less and less aggressive with your sanding, use finer grits, and always use the sanding block.
Just my humble .02 cents.
Another thing that will help you is a guide coat. After your primer dries, lightly spray some flat black paint over the area you're going to block sand. As you sand the black will show you any low spots you need to add filler to.
For a beginner this is how I would approach it:
1. Learn how to take out dents first. A body hammer and a shoe heel dolly are good to have.
2. Learn that body filler is for what remains after removing dents, it is not for filling craters.
3. Use glazing putty, not bondo. Bikes are small; correspondingly they have small damage, unlike cars.
4. Own a soft sanding block and a hard rubber sanding block.
5. Use a guide coat as mentioned.
5. When block sanding, use a X pattern rather than circles or straight lines.
6. Stop sanding an area as soon as the majority of the guide coat is gone. Evaluate what remains. Are the leftovers seen evenly over the entire surface? If there is more in one area than another, that area is lower. You will then sand on the higher area for a bit to try and bring it down to the low area. If you sand to metal you can go no further and must add filler to the lower area.
7. Practice on a junk piece. Junk is plentiful, good stuff is not.
1. Learn how to take out dents first. A body hammer and a shoe heel dolly are good to have.
2. Learn that body filler is for what remains after removing dents, it is not for filling craters.
3. Use glazing putty, not bondo. Bikes are small; correspondingly they have small damage, unlike cars.
4. Own a soft sanding block and a hard rubber sanding block.
5. Use a guide coat as mentioned.
5. When block sanding, use a X pattern rather than circles or straight lines.
6. Stop sanding an area as soon as the majority of the guide coat is gone. Evaluate what remains. Are the leftovers seen evenly over the entire surface? If there is more in one area than another, that area is lower. You will then sand on the higher area for a bit to try and bring it down to the low area. If you sand to metal you can go no further and must add filler to the lower area.
7. Practice on a junk piece. Junk is plentiful, good stuff is not.
Might get blasted for this.... but I never, ever.... yes never! use any form of glazing putty on anything I am working on.
Why? I think the stuff is just too soft. If you fill a ding with it, the area never fully hardens, and it you touch it with something, its liable to fall out. glazing putty was meant to be used sparingly... meaning very very thin, plus it shrinks quite a bit as it cures.
I havent used it in years, maybe they make better stuff now a days?
I metalwork the area the best I can, hit it with bondo to fill any low spots, sand the filler with nothing finer that 80 grit, then prime with a good 2 part automotive primer, then guide coat and block sand with 180 dry, then recoat the primer as needed then block it with finer grits up to 400 or 600 wet or even higher depending on what paint you are using.
When working with bondo you will likely get pinholes, I never use glazing putty on those either, just mix a small batch of bondo, and scrape it across the area with the pinholes, your not looking to deposit a thin coat, just fill the pinholes and scrape off the rest... let it cure then hit it with some 80 grit, then prime as usual.
Why? I think the stuff is just too soft. If you fill a ding with it, the area never fully hardens, and it you touch it with something, its liable to fall out. glazing putty was meant to be used sparingly... meaning very very thin, plus it shrinks quite a bit as it cures.
I havent used it in years, maybe they make better stuff now a days?
I metalwork the area the best I can, hit it with bondo to fill any low spots, sand the filler with nothing finer that 80 grit, then prime with a good 2 part automotive primer, then guide coat and block sand with 180 dry, then recoat the primer as needed then block it with finer grits up to 400 or 600 wet or even higher depending on what paint you are using.
When working with bondo you will likely get pinholes, I never use glazing putty on those either, just mix a small batch of bondo, and scrape it across the area with the pinholes, your not looking to deposit a thin coat, just fill the pinholes and scrape off the rest... let it cure then hit it with some 80 grit, then prime as usual.
Yeah, it definitely needs to be used very sparingly. Thinner than dust. Nonetheless, I've had luck eliminating troublesome spots with it sometimes. As long as it's a tiny amount, it's as tough (or weak) as the paint job that it covers it.
