How to make custom bumperettes

[Foster48x]

Looking good. I also hate using the fiberglass cloth, it tends to get messy. Have you tried the Bondo fiberglass resin that has the fiberglass already mixed in it? I think it comes in a green can. I've found it's allot easier to apply.

Rick

[azygoustoyou]

Yeah, I have a can of it new just waiting to go over one coat of the cloth. I want to make this stronger with the cloth first. I tried doing smaller sections. I cut a piece of cloth to fit the whole front. I mixed up enough of what I thought would cover both fronts. It's about 100 degrees now. As soon as I got the first covered. My resin hardened and I didn't even have enough time to clean the brush. I'll try to get up early tomorrow to do more. It's too hot now and I don't have anymore brushes. It seems your going to need a few brushes and several plastic cups. At this rate. It's going to take me till the weekend to finish.

[azygoustoyou]

Hi all,
I wanted to give an update of what I'm doing with the bumperettes. I decided to use these bumpers to make a mold. The finished ones will be made of fiberglass. I would like to say this is a fun project.
It seems after I put on some of the cloth and then sand just a little to smooth it out. I would end up taking it down to the wood. So I would suggest to put on at least three coats of resin after the cloth to smooth it out. This is the final coat of resin on the bumpers. I'm going to use some fiberglass resin jelly to cover or smooth out what I have here. Then I'll final sand them to their finished shape which is still very close to what you see. The next step will be to make the molds.

[bwilson27]

Thanks for the update. Will you lead us through the mold-making process as well? I'd be interested to how how you do that.

[azygoustoyou]

Yes, I'll finish this step by step process. You can see, it is turning out to be a very long. Yet I will have my own custom bumpers in the end. They should last as long as my car does.

[azygoustoyou]

I finally have the bumpers covered completely with resin. I hand sanded this one with 180 grit and a square sponge to insure a even smooth appearance. The better the piece to be molded, the better the product will turn out. Just think of it as, your bumper will look as good as the item your making the mold of. I'm painting mine with bumper touch up paint. I could not worry so much about the quality of work for the item to be molded. I could have spent the same amount of time on the finish product if I was only intending to make one set. I have to say for as much time I have spent on these. It would be cheaper to purchase other sets for the $366 price tag if time isn't something you have a lot of. I'm hoping the process gets faster since the outside surface of the bumper will be perfect within the mold. I did see online somewhere that you can tint the resin. You could tint the first few coats in the mold to give a colored sheen when the product comes out. I like the rubber look though.
I searched online to find out what to use as a release agent for the mold. I was hoping to be able to purchase something local. It always seems I have to order auto body items because nothing is close. Then I came across a post that said you could use Bowling alley wax. What do you know. I have some. It also specified to wax the item and wait 2-3 hours. Wipe off the wax and wax it again. You want to wax it about three times to insure you'll be able to release it. I'm going to do one bumper at a time. If I make any mistakes. I don't want it to be on all of them.

[azygoustoyou]

Today I was able to sand both fronts. Wax the first. It's ready for a mold to be started tomorrow. Start waxing the second. These things look perfect. I would even feel comfortable using them on my car. They are sealed well.

[azygoustoyou]

After preparing the first bumperette with wax. I cut fiber cloth. Two pieces for each side not going completely to the corner. Last time I had a hard time getting it to lay flat. I cut small pieces to cover the corners and to overlap onto the top and sides. This was much easier. I had to find something to hold the bumper off the table. So I used a spray can lid and screwed it to the bottom. I mixed up two ounces of resin. I laid the top on first. Then the sides. Used the small pieces to connect them. I then put the second side pieces on and finishing up with the top. Maybe I used a little too much resin on the sides. Because gravity took hold of the second layered side piece and it drooped. Nothing I can do about it now. Maybe I should have had tabs on the side pieces to overlap onto the top. The first attached side pieces did stay in place. As I was just about to finish with the second layer top piece, the gel started to gel up. I got enough on to hold it there pretty good. As you can see, the bottom of the plastic cup melted. I guess I should have bought a better cup. Well, if it lasted long enough to get the gel out. I'll just keep using them. I'll have to remember to have the cardboard under it.
Oh yeah, my wife is at work. So I thought I'd have a better chance of doing this inside where it's really cool. You know, give me more time to attach the pieces. Now I have the air off and have all the windows open hoping to clean the smell out. If I'm not back on tomorrow. You know what happened.

[azygoustoyou]

Okay I got the smell out of the house. I'm pretty honest so I told my wife. I know, you don't even have to say it.
I trimmed the extra cloth hanging off the bottom and left about 1/4". I put on the second coat. I cut off the small spiny pieces near the edges that wouldn't let the new fiber cloth lay flat. I cut some fiber to go from the sides to the front and to wrap around the from the sides to the top. I didn't wet the cloth as much between the layers. Last time it was really thick. This time was just enough to wet the cloth and it worked well. You want to always make sure each layer has enough resin to completely wet the cloth. When you cut the pieces. It wouldn't matter if you used all small cuts. You just want to make sure the whole surface is covered and the cloth overlaps to insure a strong mold.
This is a good project to do even when it's raining. It's pouring here! Expect to waste a lot stirring sticks and brushes. The cheapest I found to buy brushes is at Walmart. They cost $1 for the 1" Anything bigger would be too hard to work with. I tried cleaning the brush with Lacquer thinner but was just a waste of time. So expect to only use the brush one time.

[azygoustoyou]

I got the first bumper mold done. I saved all of the stirring sticks to use as reinforcement within the mold to help it from deforming. I figure I had put about 6 layers of the resin and cloth on. I then used the fiberglass jelly and covered each side of the mold. I did one side at a time so I could hold it. After putting about 1/8" of jelly on. I pushed the stirring stick into it. You want to put the stick on as few pieces as possible. I used one for each side. One for the top. Two for the bottom front and three for the front. After I got the whole thing covered. I mixed up some more jelly and filled in all the areas and made it solid.
Lets see how it comes out tomorrow.

[bwilson27]

There's no way to re-use these molds is there?

[manoa matt]

Brady, there is a much easier way. Use the MDF blocks as molds, cover them with wax. Mix and lay up the fiberglass. Place it in a vacume bag and suck all the air out and let it cure. Take it out of the bag and pop the glass off the MDF. No secondary mold and the glass matt conforms to the surface perfectly and no little hairs at the corners. The best surfboards are made using a vacume bag technique.

[azygoustoyou]

I wish I would have known that in the first place. The thing is I was going to use the blocks as the bumpers. The more I thought about it. I just wanted them to last. So it took a curve and I did it the long way. Just documenting what I had done. I sure there may be other ways also. Like using foam to carve out the bumpers.
I would like to think that the molds will be reusable. Let's wait and see.

[azygoustoyou]

Wow what a struggle. I didn't think I was going to get it apart. I did ruin the product though. At least I got it out. I would rather have the mold. I hope I can get the bumper out a little easier. I don't know what I could do to make it easier. I waxed it a lot. The paint that I put on the MDF was good to help seal it so the fiberglass wouldn't just sink in. Though it didn't help completely to hold the product together. It split and a small piece of it stayed in the mold on the corner. I had to scrap it out. I will have to fix the inside of the mold somewhat where I scraped and pried it apart. I don't want this to be a waste of time so after I fix the mold. I'll make the bumper.

[azygoustoyou]

Hi all,
I just want to reiterate "I'm no professional and there may be easier ways to accomplish this" I'm using the stuff I have and trying to keep this as cheap as possible.
I have accomplished the goal of getting a good mold out of the MDF bumperette. After seeing it come apart so easy. I'm glad I didn't just stick with it. When I was taking out the bumper (product) out of the mold. I used a razor to scorch the edge to release any access resin that might hinder it from releasing. That also gave me a line to grind the extra fiberglass away. I used my hand grinder. I then hand sanded inside the mold to smooth out any damaged areas or areas that needed touched up. Don't sand anything that doesn't need it. I used some spot glazing putty to fill in the imperfections. I'll let it sit until tomorrow. Then I'll smooth it out.