I'm going to make my first attempt at a bead seat tomorrow, and I was wondering what other guys have used , by experience, for a bead to epoxy ratio - in other words - how many ounces of epoxy for a 2 cu ft quantity of beads?
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I'm going to make my first attempt at a bead seat tomorrow, and I was wondering what other guys have used , by experience, for a bead to epoxy ratio - in other words - how many ounces of epoxy for a 2 cu ft quantity of beads?
2 cu ft is really small. Just pouring a little butt pad sized thing?Quote:
Originally Posted by Rick Kirchner
The Bald Spot kits I sell (this is a guess since I am at VIR and don't have any in front of me.) but for a 10 gallon kit I am thinking that the two parts are each about 12-15 oz each.
It doesn't take that much. Just do a very good job of coating the beads and the mix should be fine.
Also before you get in to sit in the seat to do the forming try to get as many of the wrinkles out of the bag as possible. It allows teh beads to fill in voids where the bag might.
If you havne't picked up any epoxy yet, get stuff you can work with for at least 20-30 minutes so you aren't rushing.
Rick,
Cooley is right.
We did one last year. If Jeff see's this he may remember the qty. details.
I know when we started my reaction was NO WAY will that mini-amount of epoxy/resin do this job. But it did. The secret was massaging, squeezing, stroking and rolling to get all the beads wet. Spent at least 15 minutes doing it. So make sure you epoxy/resin isn't a real quick cure.
I think if you over saturate you'll end up with a stone hard seat. If you under saturate the beads fall off. However, if after the cure you see you have a lot of loose beads just trim and tape the bag without trying to remove the whole bag.
I bought some nylon vacuum bagging tube - 36" wide, sealed up the bottom with vacuum bagging "tape" (it's more like putty) and doubled it up with some clear flexible sealing tape.
I'm using Jeffco Aeropoxy with a 1 hr pot life hardener. I was going to get the 2 hr stuff, but the Jeffco guy thought the beads would do such a good job of insulating the epoxy from itself that it might require an extended heat cure.
I'm 6' 215lbs in a 94 VD, so 2 cu ft should be enough - at least when you put the bag in the car it looks like more than enough!
Based on the remains of a kit that Daryl DeArman gave me, and the notes in this thread, I'm thinking about 6 oz.
Quote:
Originally Posted by cooleyjb
2 cubic feet is more than 12 US gallons dry.
Rick, I don't think what I gave you will be enough for 2 whole cubic feet. Then again, I don't think you'll need that many beads, no offense, to fill the voids in your cockpit. Mix the epoxy at the appropriate ratio and utilize just enough to get all the beads a very light grey.
I ran some tests with the stuff you gave me and then picked the Jeffco stuff. Here's a pic of the bag - it's 3' x 5' and about 2" thick evenly distributed
Make SURE you put cardboard where you do not want the beads to flow. We had our cockpit well sealed off to avoid beads getting between the frame members. Missed ONE small section just in front of the front hoop by the fire handle. It proved to be a BEACH getting it out with just a little wraped around that tube and a few other little problem areas.
Depending on the shape of your cockpit, don't be surprised if you need to cut the seat just to get it out.
No clue what your epoxy/resin consistancy is. But if it's anything like supplied with kits, I would think 15 oz each would do it. Just MIX the mess together really good and have some tape handy in case the bag punctures.
Hope you have somebody there to help work the beads around once you sit down.
Rick,
I recently did one and used a 50 to 1 ratio - guess and eye ball scale.
I ran some quick numbers and that seem to agree with others' comments.
In the forming process you may want to use less vacuum than a vac cleaner generates.
Put several side holes in the vac hose (use an 1/8" drill) that goes in the bag to keep from sucking the bag in the vac hose.
Also, use a leaky hose outside the bag to control the amount of vacuum wanted.
Cut the bag to fit your car and use light weight boxing tap to tape up the cut sections.
Use same tape to tape up top of bag and hold hose in bag.
I used latex caulk to seal the surface and bind the nomex cover. Cover laid up ok on ouside but had to bag it and use a vacuum pump to get bonding on the internal concave surfaces. Vac cleaner not enough in my case for the concave side. Had about 15 in Hg. on over night.
Latex caulk provided a soft, flexible and robust surface. However, it did add significant weight. I used upward of 4 tubes. Bead finish was a bit rough in spots and it took forever to fill in the voids with caulk and beam mix before putting on the cover.
The most surprising part of this seat is that when strapped down in it, I do not feel the seat - no pressure points.
I had a fellow FF driver help with the process. This is not a one person job.
Wishing you success.
so far...
Started at 0730 this morning. Mixed up 15oz of epoxy and pigment. I hit that spot-on, pretty much a perfect amount for 2 cu ft of beads. It only took about five minutes to get it mixed well - the Aeropoxy is pretty thin stuff.
Rolled the beads out with a piece of PVC pipe and placed the bag in the car. Got in and immediately realized there was too much fill. It was good that I had such a big bag because the excess fill had to go somewhere. I'm thinking 1.25 to 1.5 cu ft would be about right.
Made the best of the situation, used assorted rollers and my hands to move the beads around. should have paid more attention to re-sealing the bag. My pump can only pull 3in Hg because of a slight leak at the top of the bag. I have to figure something out because the pump is getting pretty hot and if I turn it off the bag relaxes quickly.
The big suprise is that at 2 pm the stuff hasn't begun to cure yet. I rolled it out into the desert sun and put a 55 gal garbage bag inside with 15 gal hot water (the sun heats the bag to the point where you can't touch it for more than a second or two). The water provides enough weight to keep the vacuum from changing the shape> I was hoping that the heat would help kick the epoxy but so far no joy.
I'm going to end up trimming off almost everything above the radiator ducts on the sides, the stuff in front of about halfway up the firebottle cover, and about 6" down from the top. At least this stuff won't be as nasty to grind as the pour foam!
Rick,
Let it cure. The LONGER the better. We did ours on a fairly cool day. Had 2 500 watt heat lamps on it and even after 24 hours the beads still felt too "spongy" to think about removing it.
Looks like your thickness isn't too thick. Be real careful removing it. That stuff whill snap in half real easy. Just a little stress is enough. If you need to 2-piece it, do it as you remove it. A well heated knife with a propane torch works fine. Just don't make it your loved ones favorite slicer.
If you need to do some shaping, put VERY LITTLE stress on it. Try to do most of it with a hot knife or GENTLE sanding. Once you get the final shaping and tape on the beads, it's pretty sturdy.
2 cubic feet. Durrrr..... I can't read. I was thinking 2 gallons.
As for cure time. It should take a long time. The ones I pour cure overnight to a good set. They are recommended to stay on vaccum for eight hours for the initial set.
Around 1730 the stuff finally gelled - about 10 hours form the mix. So, I'll let it sit overnight and firm up.
really cheap. Here's my shoe string experience for those thinking about diving into this project cold.
I have lived with a "starter" 2 part foam seat made for the previous owner for the last 4 years. It's worked OK but I've always wanted to go the bead seat route. So, I got together with a buddy and we made a couple-3 attempts with locally procured TAP plastic materials as has been so well described in several older threads. We didn't come up with anything that we were proud of and it became obvious the devil was in too many details that no one mentioned or that seemed trivial but really weren't.
So we finally called Troy Stevens from Fairfield, CA to come over and do us both on a weekend. And it took all weekend with him fitting us in the car, checking all the ergonomics and producing something that provides far far more protection, never mind the comfort, than we could have if we had tried another dozen times. It all sounds easy and low tech, but there's no substitute for experience to get it right and look good too.
After watching him work and seeing the product, I figure if a guy buys more than one set of tires per year, he owes it to himself to get a pro made bead seat. That's a decsion threshold I have not seen discussed. JMHO
Troy is at Troy@racecarseat.com 1-707-372-7162. For being a well seasoned pro and fitting some high profile teams, he remains a nice guy who's easy to work with. :greenflag: :trophy:
No affiliation, just a satisfied customer. :thumbsup:
To answer the previous question, it takes 48 ounces of epoxy mix for 20 gallons of beads.
Ted is correct. To make a proper seat takes a few tricks and a lot of time. It usually takes me about 10 hours to trim, add the Kevlar backing and cover the seat after it has cured.
Dean
I've spent way mor time than that and I'll probably make a second version now that I've figured a few things out.
It's easy for you guys in metropolitain areas to get pro-built stuff. I'm a 7 hour tow (and 75 gallons of gas) from the bay area.
Quote:
Originally Posted by Rick Kirchner
Two of the biggest keys to 'pro built' that I have found are the tools. The low pressure vaccum pump and a hot knife make a world of difference when pouring and then cutting out a bead seat. Sure there are a few little tricks but most of the tricks are taking your time to do it right. You don't have to rush because the epoxy has a good amount of work time.
Rick, Ron Roland had a team called R-Sports out of the Bakersfield neighborhood area. He's now the Comp Director for Star Mazda. IIRC, he was known for doing some pretty good bead seats. You might try getting in touch with him on the off chance that 1) he still has a home in your general area, and 2) still does bead seats or 3) knows a good seat guy down there. Of course if he's not there, Star must have a seat guy of their choosing as well. And since there's not a lot of material or equipment to haul, paying expenses for them to come to you might make sense. Just a thought.
thanks Ted - If I don't get this right on the second try I'll give him a call. When I bought all the supplies from scratch I had enough to make at least three seats except fot the beads, which you can get from J0-Anne fabrics for $25/bag.
The first thing I did wrong was use the whole bag of beads. Although the bag I fabricated was 3' x 5', when I got in the excess beads went as far as they could go. At that point I was just making a seat that was too small. When I gathered up all the trimmings, they amounted to half of the starting bag - so I could get by with a 1 cu ft quantity of beads to start.
A couple of things I learned along the way:
It's better to trim the seat with the bag on it if possible - it helps with structural integrity. However, using hand tools in this configuration is difficult, because the nylon bag is pretty tough.
after you pull the bag off a lot of loose beads start coming off. If you paint the seat with some of the epoxy mix, it will develop a lot more structural integrity.
You can take trimmings, put them in a blender, and return them to a single-bead state. I mixed up epoxy with loose beads and used it as crack and void fill. This fill is easily re-shaped with a flapper wheel.
After fooling around with three foam seats, the stock fiberglass seat, and the bead seat I've finally realized that with the stock seat I'm sitting on the floor anyway. The stock seat just makes it hard to get in and out. All I really needed below tha waist was a couple of foam pads on the sides next to my hips. What I need the bead seat for is support on my back and to keep me from moving side to side. The seat needs to be really thin under my spine or else I'm too far forward.
So, I'm going to make something that goes from the bottom of the fuel cell to above my shoulders and outside between the frame tubes. Then I'm going to cover the back with a layer of kevlar. Then I can trim the inside for more volume if necessary. what this method does is use the inside of the car to form a mold for the backside of the seat, and uses your backside to form a mold for the frontside of the seat.
Rick,
Thanks for the running account and the frank feedback.
Bill
I don't think I have EVER met a customer of Troy Stevens that thought the results were not Worth the cost.;) Even ME,and I'm almost as Thrifty as The Purple Frog!:o
basic supplies:
36" bag tube, sealing tape, connector, kevlar: http://www.acp-composites.com/acp-vbes.htm
epoxy: http://www.ptm-w.com/index.asp?pgid=176
Beads from Jo-anne fabrics. There are other suppliers, but shipping is astronomical because of high volume.
I went to Richard Morgan Racing in Charlotte to have mine done. Here are the steps we used.
1. Put the beads and vacuum tube in the bag and seal it
2. Put bag in the car and push beads around as needed.
3. Sit in car.
4. Wiggle around and push the beads around until you are in you driving position. Estimate how much excess beads you have.
5. Pull bag from car and cut slot to remove excess beads.
6. Mix resin and add to the bag (We only used about half the resin in a BSS medium kit). Reseal slot with a piece of duct tape.
7. Need the beads around to distribute the resin.
8. Lay bag in car and climb in.
9. Wiggle around to get into you driving position.
10. Pull a good vacuum and very carefully get out.
11. Look at the seat and make sure everything is where you want it.
12. Reduce the vacuum and pull the wrinkles out of the bag on the seating surface.
13. Increase the vacuum and sit in the car until the resin sets (30min to 1 hr).
14. Let it cure overnight.
15. Cut the seat as needed to get it our of the car. On my KBS F500 we cut the seat in half right down the middle with a beveled cut. It took almost an hour just to get the seat out the first time.
16. Trim any other trouble spots as necessary and then tape any cut areas.
We did not remove the bag and there really isn't any need to. The bag acts to keep any beads from shedding off the surface and you won't need to go back and fill the surface with anything. Once I finish rebuilding car and get back on the track once or twice and 100% happy with the final seat, I will cover it with either cotton or Nomex fabric.
Fellas;
To get the seat out of my cockpit, I had to do some trimming. As you would have it, "I cut three times and it is still too short". Anyone have a few cups of beeds as well as leftover epoxy and catalyst?
Iverson
Rick - take your trimmings and put them in a blender. You'll have to experiment a bit but I mad a coffee can full after I made my seat.
Good thinking, Bud
Won't the margarita's taste funny?;)Quote:
Originally Posted by Rick Kirchner
having done more than a a few dozen seats, just some quick comments
some really good info in this thread.
Beads - the beads from the fabric store may be the best value for money. If you are near a large city, look for companies that make foam insulation, and ask them for raw unsorted beads. In Denver a huge bag (maybe 30 lbs, bag is approx 3'x3'x5' cost $30 - enough for about 8 or 10 seats
Epoxy - I prefer West System because I have yet to have a bad batch of epoxy from them. The mini-pumps make measuring the epoxy a breeze, and they offer 3 speeds of hardener 205, 206 and 209. The 206 is appropriate for temps 70F and above and will give approx 35 - 45 minutes of work time. Use a painters tray rather than a plastic pail and the mixture wont cure as fast
Vacuum pumps - Harbor Freight sells an A/C vacuum pump for about $20. You will need a fairly substantial air compressor to provide about 3CFM at 90 psi. Or if you are stuck (or broke) dont hesitate to use the Crafstman shopvac. Just noisy, but they will run for a long time and pull a reasonable vacuum
Bagging material - a large clear garbage bag is substantially cheaper than specialized bagging material. You can even avoid using bleeder plastic, and a breather layer, but will need more prep prior to covering.
Formula Cars and Sports Racers take about 10 - 15 gallons of beads. The earlier advice regarding "dry fitting" prior to mixing epoxy should be heeded. For each gallon of beads you need about 1 fluid oz of mixed resin. Any more and the expoxy will kick off faster. you can mix a dye (food coloring will work in a pinch) so you can "see" the epoxy coating the beads.
1 piece seats are better than 2 piece, and never split the seat vertically (or along car centerline), the seat MAY split apart if you backed the car into a barrier. My personal preference would be a slightly smaller single piece seat bolstered with foam if needed over a 2 piece seat. But your cockpit shape will be a determining factor.
HTH
Grant