Well im repainting my car soon, and on the bumper there is a ton of little hair line cracks, how should i go about getting rid of these? Also how would i go about getting the front bumper off? Thanks in advance.

 

spider cracks are caused by someone respraying a bumper or a shop spraying a new replacement, when the shop does not use some kind of flex additive to their clear coat. after the product has been sprayed the clear coat is too hard and will become brittle this will cause what are called spider cracks at any point that a flexible surface is allowed to flex or if the object is hit, even very minorly, it also will cause this. The only solution is to sand the substrate to the bare surface in this case plastic. I recommend using 80 grit on a random orbital da sander followed by a polyester glazing puddy, sanded with 180 grit wet blocked followed by a 2k primer blocked to 6-800 grit depending on the desired base coat. No mater what finishing technique you use the cracks MUST ALL be sanded out if you do not want them to show through your final finish. Base coat can not fill these type of cracks.

 

Where can i get this glazing puddy? And when i respray my car im doing it myself, i was going to use duplicolor clear coat, will this be okay on the bumpers or no? If not where can i get clear coat that will work?

 

Just ask for a flex agent to be added to a quart or so of your paint when they mix it, and only use that quart for the abs parts. That goes for both the base coat and the clear coat.

 

they also make a plastic striper and when you go back to prime make sure you use an adhision promoter for the type of paint you are doing. the primer should be able to have flex aditive to it or use a primer for plastic as for flex additive make sure it is in the base coat and clear coat it needs to go all the way through your coatings. at the paint store they should be able to help. as foar as gettingthe bumper off ypu go through the wheel wells to get to most of the nuts.

 

Well as i said before i was going to buy dupicolor paint premixed forom an autoparts, can i do that then mix flex agent in if i can buy it? Or is there anywhere i can get paint with flex gent alreay in there?

 

I would see if napa has a paint supply store in your area if you are looking to do things cheaply, they have the cheapest paint supplies otherwise you need to find a good paint shop aka jobber in your area. Let them make paint recommendations. I use a huge variety of products daily and use each according to the job,(a good painter still has problems, how you deal with problems is what can make you a good painter) As far as glazing puddy goes there are many brands west coast and east coast use very different products where you are will dictate what you can get, but like I said let a paint store make recommendations, they will account for things like the equipment you have and product compatibility. Other than that dupicolor is walmart crap(not to hurt your feelings). If you don't have spray equipment buy some (craigslist is your friend). If you can't do that then do all your prep work, good paint is all about the prep work, go to an auto paint store and ask about scuff paste, it is by far the best prep just remember to wash it off really well with water, be sure that you remove EVERYTHING that you can on the car, (look at how much I took my car apart, it is the thread near the top under the body forum"92 rs 25th rod project") after it is good and scuffed fill and prime any imperfections, and never rush anything get at least two blocks to use when sanding one that is flat and about 12 to 14 inches long and one that is 5 to 6 inches for tight areas. If you are smart you would do what I am doing and use a 2k primer on the entire car then after that has dried you take a aerosol can of black paint and just dust a little paint over the entire surface, this is called guide coating. If you use the long block with 4-800 grit sand paper (400 if your base coat is a solid color, 600 for dark metalics or pearls and 800 for fine silvers or light/fine metalics) you will see lows like waves and door dings in the guide coat like night and day. when you knock down the primer's texture with the block you are trying to sand all the guide coat off this tells you you have a paintable surface. so long as you keep the block flat as you sand you will not be able to hit the lows and this tells you to use a little more of that glazing puddy, just a thin skim, then block that down and you will have a really nice surface to paint on. Prep is what you pay for in a body shop because it is the most time consuming process. If you can do all your own prep work so that all that a shop has to do is clean and shoot you could get a $10,000 paint job for $1,000. The real question is how much is your time worth to you. Sorry this is so long, but there are not too many people out there that will tell you how to do a job right.

 

plastic stripper is really pricey it costs about $40 a can and it takes three cans to strip a whole bumper. sand paper is much cheaper. you do not need a flex agent for primer or base coat that is just way over kill. I never have problems with those layers. If you use too much hardener in a catalised primer such as 2k you could have a problem, or if you exceed the recommended mil thickness and just poor on primer. the two areas that I see the most problems are people using cheap fillers bad prep with no grit for a mechanical adhesion and not thoroughly cleaning with scuff paste and wax and grease remover. OR using cheap clear coat. I hate clear additives some people will use fisheye eliminator, accelerator, and flex agent. they just don't understand why they have warranty issues. Just use a good clear that has a nice resin to it and you will not have to add anything at all and will not have any problems. I have not had a single job come back in 3 years (working six days a week) and I do not add anything to my paint or clear.

 

Wow thanks for all the help, i have a lot of work ahead of me haha