slight door ding blocking advice, help!

B

bmxpegan411

Hi Guys,

I'm using Evercoat Slick Sand to try and finish the doors on my Honda Del Sol, but it seems each time I apply a few coats and block it off I keep getting back to the same stage I was before I started blocking. there are slight door dings down the middle of the panel, and you can't see them unless the panel is wet or hit with something fine and are pretty much eye level/behind the door. I've used guide coat and blocked it out, but it seems the dings remain. Again, they're VERY slight, but I don't want to live with them.

For the sanding I'm using a harbor freight long block, 80 and 180 grit paper and cross hatching the whole door, not putting alot of pressure on it. Since I've gotten the same results I tried using a soft block and I still seem to have the dings. do you guys have any tips/advice for me? Here are pics of del sol doors, but I don't have one of mine yet. The black one, between the red arrows down the door is where they are, and they are similar to the dings on that blue car, just not near as bad. door ding 1.JPG

door ding 2.JPG

door ding 3.JPG
 
And when you're blocking at what stage do you stop? Can you post pics? If you're blocking down to bare metal and keep going it is possible to undercut the areas where the fill is needed even if you're using a rigid block.
 
My first recommmendation would be to block with 180, 80 is a littel course for blocking primer IMO. Also if you are trying to use teh hardwood block, it is probably not going to work well because of the slight curvature of the door, but a soft block will be too soft. So, I would recommend either investing in something like a medium length dura-block style block. Also if you have a yard stick laying around, you can take a little time to sand off teh sahrp edges of it and cut a 12" piece of it to use for a block. What you need is something hard enough to maintain a flat surface and not cut the primer out of the low spots, but flexible enough to conform to the door so the ends don't cut the primer out. Also you said cross-hatching the door, so you may already be doing this but if you are not, you need to be sanding at about 45 degree angles in each direction. If you are sanding up and down, then back and forth, you will have problems with it as well. Hope that helps a little, I am sure someone has a better solution or better explanation.

Kelly
 
Hi Bob,

I go until I start to see SLIGHT bare metal, and stop to avoid the undercutting. I'm trying to keep the amount of product on the car as minimal as possible to avoid issues in the future. Here's a pic of mine before I blocked it to get an idea of the curves. I'll get some pictures of the doors tonight in their current stagedoor ding 4.jpg
 
This might not be related, but the appearance of door dings in cars like that can sometimes be caused by applying too much pressure on the block. The door skin is supported by blobs of foam along the intrusion beam, and applying blocking pressure in these areas will result in more material being removed from the supported areas, producing the appearance of a ding or wave. If the low spots correspond to the foam spots inside the door, this is the problem you are having. There are many ways to minimize this appearance, starting with less sanding pressure, easier to sand materials (poly primer is not known for easy sanding), and adding more support along the intrusion beam.
 
bmxpegan411;31003 said:
Hi Bob,

I go until I start to see SLIGHT bare metal, and stop to avoid the undercutting. I'm trying to keep the amount of product on the car as minimal as possible to avoid issues in the future. Here's a pic of mine before I blocked it to get an idea of the curves. I'll get some pictures of the doors tonight in their current stageView attachment 2695
Click to expand...

I bet Crash is right about the intrusion beam glue spots if these imperfections align with the beam. Another thing to think about when using heavy build surfacers like poly primer is it's easy to get a high buildup in areas where you don't want it, you can mask off the perimeter of the handle hole before you prime to keep the buildup out of that area. Other common areas to consider masking are cowl vent grilles, window openings, jambs, fuel door pockets, tailamp pockets. It's easy to get too much primer in these areas and not have parts fit come time to reassemble.
 
Bob Hollinshead;31021 said:
I bet Crash is right about the intrusion beam glue spots if these imperfections align with the beam. Another thing to think about when using heavy build surfacers like poly primer is it's easy to get a high buildup in areas where you don't want it, you can mask off the perimeter of the handle hole before you prime to keep the buildup out of that area. Other common areas to consider masking are cowl vent grilles, window openings, jambs, fuel door pockets, tailamp pockets. It's easy to get too much primer in these areas and not have parts fit come time to reassemble.
Click to expand...

thanks for the heads up. I didn't work on my doors last night to take any pics, but I did run into the issue you guys are mentioning when I first started working on the car on the trunk. I found it odd that I was burning through spots that were in a symmetrical pattern, lol.

next time I block the doors I'll go extra light and see how it works out. Is there anything besides a durablock that you guys suggest for this?

for extra reference I found the exact same type of dings that I'm trying to get rid of, and this car was indeed painted since they never came in orange.door ding 5.JPG
 
That looks exactly like blocking induced waves, to me. But pictures aren't like being there...

If this is what it is, switch to a coarse grit, and just slide the block over the surface, with just enough pressure to keep the block on the surface. This is time consuming, as in it will take forever! Put something on the radio and bring a lunch, lol. Then you can reprime with some regular 2K urethane, as it will be easier to sand with light pressure.

If you can get more foam between the skin and the beam along its entire length, that would help immensely. Usually you have to put a length of hose onto the applicator tip to get it done.

Having the door off during all of this will also help, to allow the foam to stay under the beam and not run out, and to reduce fatigue while blocking.
 
crashtech;31026 said:
That looks exactly like blocking induced waves, to me. But pictures aren't like being there...

If this is what it is, switch to a coarse grit, and just slide the block over the surface, with just enough pressure to keep the block on the surface. This is time consuming, as in it will take forever! Put something on the radio and bring a lunch, lol. Then you can reprime with some regular 2K urethane, as it will be easier to sand with light pressure.

If you can get more foam between the skin and the beam along its entire length, that would help immensely. Usually you have to put a length of hose onto the applicator tip to get it done.

Having the door off during all of this will also help, to allow the foam to stay under the beam and not run out, and to reduce fatigue while blocking.
Click to expand...

thanks for all the info Crash. Would something like styrofoam work? and should I lightly cross hatch the whole door, or just the mid section?
 
No styrofoam, you'll need a material like SEM 39357 or equivalent, that can be applied between the beam and the skin, and will expand and set into a nice flexible foam. The rigid foam sold at hardware stores will NOT work!

If I was doing the job, I would want any excess film thickness removed from the repair area, because overly thick primer just makes the panel more chip-prone. But how much you block in the areas that aren't a problem is up to you.
 
update! Crash and everybody that said it was from too much blocking pressure was right. It was boring, and tedious, but I took some 80 grit on a 17 inch block and just pushed it across the panel with NO pressure and got the drivers door laser straight. it took like 3 hours, but I can finally move on, and hopefully get the car finished this weekend.

thanks to everybody for the great advice!
 
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