Anthony Fairhurst

Hi John - Mainly looking for the PID temp controller with Bluetooth capability. I'm not fully interested in vacuum just yet but am sure others would be interested in seeing what parts are needed for that. I'm also looking for a good temp recorder that doesn't cost an arm and a leg like the Graphtec bricks! Or can the PID/ SSR/ Phone app record all that? Thanks!

Hey John, This is by far the best and most legit DIY curing oven I've seen anyone build! Could you provide a parts list to this build? I'd like to try making something similar for my disc projects! Thanks!

Thanks John! the gap between the top and bottom platen is 0.04" so with 4 plys of fabric (CPT 0.011") it should be enough material. On the 2nd iteration I used 6 plys but now believe there simply is no way for air to escape! What type of vents do you envision? I could Dremel out two small channels from the cavity to resin trap, and resin trap to the pry slots on the edge. Would this suffice? Along the lines of SQRTM, I was hoping to try a mix of wet and prepreg layup - essentially laying up with prepreg and adding some extra resin into the layup. Otherwise I'd also like to try a fully wet layup as well as a vacuum cure of each induvial side. However, I will need to devise some special toaster oven. I think there's a good post about that somewhere.. 🙂

Hi Mongo, There is just about anything on the internet! I found a pretty cool webpage, "History of Rivets & 20 Facts You Might Not Know" where they note some megastructures assembled with rivets. Unfortunately there is nothing about composites on this webpage but interesting nonetheless. However, seeing as rivets are typically permanent fasteners, this is not a good joining method to be used with carbon fiber panels in super strong structures expected to last a long time. The reasoning is the effects and presence of galvanic corrosion. You can read more about galvanic corrosion here. Basically carbon is electrically conductive and upon contact with actively corroding metals, the difference in electrical properties will cause ions to be pulled from the metal to the composite and corrode quicker over time (3-5 years instead of 10+)*. *Please note I am not a chemist or metallurgist so my "dummy's statement to galvanic corrosion" is coming from a dummy! Best way to join composites is bonding. Second best is bolts as they can be easily replaced if you were to notice any corrosion. One way to reduce the risk of corrosion is by placing a barrier in-between the metal and carbon, such as fiberglass, plastics, or other non-conductive materials. Hope this helps! Anthony

Hi All, I recently decided to combine two of my passions, composites and disc golf! I started with making a splash mold off a full size disc and it went.. OK. First part tore off the gel coat so luckily I was able to salvage the part and may be able to save the mold. But lacking patience, I decided to try another splash mold and that went worse than the first (see my other post)! I plan to make another splash mold this weekend with some lessons learned in gel coat thickness and patience. Anyways.. because a carbon disc is dangerous to throw and not legally allowed for PDGA play, I decided to start another project in which I could make and use composite products for tournament play. Mini marker discs ("mini's") are used in disc golf as markers for where your thrown disc lays. The rules state, "Mini Marker discs must have a circular shape, with a diameter ranging from 7 cm to 15 cm and a height not exceeding 3 cm.. mini marker discs can be made from a variety of materials (e.g. plastic, metal, wood)." With that, I modeled a mini mold in CAD and sent it through Xometry.com to get an aluminum mold made. 7 business days later, I received the mold in the mail and spent hours polishing the cavity to a mirror finish. I originally planned to do wet layup as done with the splash mold but since this is aluminum, I decided to try using prepreg. I laid up the first part in 40 minutes with 4 layers of fabric on the top and chopped bits of prepreg packed into the rim. Since it was 10pm (bedtime), I tightened up the mold and placed it in the oven at 275F for 3hrs. In the morning, I easily removed the part thanks to many layers of release to see a cured part but with a ton of porosity and little to no flash. 2nd part was made with more material and rolled up uni in the bottom rim of the disc. The mold did not close up at first (as expected) so I placed it in the oven at 175F for 1hr and tightened the mold before putting it back. I retightened after another 20 minutes before throwing it back in and turning the oven up to 275F. After getting the part off in the morning I had much more resin flash with less porosity on the faces - less not none! With that, I am going to try a wet layup so I can get closer to porosity free parts. I also spent a few minutes searching for some expanding sheet material as this is one thing greatly missing from this project - pressure. I was unable to find sheets or films available to the public - only this Syntactic material from Toray. Does anyone know of such products I can incorporate to get some internal pressure. Or any ideas how to reduce porosity with such a mold? Some pictures of the tool, process, and parts below; Pretty Tool - took longer than I'd like to admit to get it to this finish! First layup - cutting up prepreg fabric for a "forged" rim was difficult as it bunched up and turned into unworkable globs. I think next time, I'll try freezing it and cutting it up so it's more flakey. (green mini disc reference in background!) First part - little to no flash and tons of dry spots 2nd part: Good flash and less porosity

Thanks, John! I found a great article on this topic where it answered some of my question and you wrapped it up! In this article they explain this texture, which as you say, can occur from too thin of gel coat or multiple layers applied too quickly and results in "Alligatored" texture on the plug side (pictured below). I also did notice this texture was only occurring in thin spots so reasoning checks out! This article covers a ton so let me know what you think of it! https://explorecomposites.com/articles/tooling/building-open-molded-production-tooling/#gelcoat What do you mean by "waiting a bit longer" before applying the epoxy? I thought waiting for the B-stage (gel coat is tacky but doesn't transfer when you touch it) was the proper application time. Should I wait an additional 10 minutes after the gel coat hits the B-stage? I will make another mold this weekend with 2 coats of gel coat to ensure good coverage before applying the epoxy reinforcement. Also excited to use a slower hardener so I am not racing against the clock!

Hello, I recently made a couple molds for disc golf discs and have run into some issues that I would like some help on. Molds were made with a polyester gel coat down first and then after hitting the B stage, the reinforcement was added with Entropy Systems CLR resin/ CLF fast hardener and increasing weights of chopped strand fiberglass and finally woven carbon. I will use a slow hardener on the next one as the fast hardener kicked quickly and got very hot during the laminating process! After both halves of the mold were done, the strong scent of polyester was still coming off so I figured it had not fully cured. I put the mold halves in the oven at 150F for 4 hours and when I pulled them out, I saw parts of the gel coat bubbled up and could flake off, exposing the resin below. What is the cause of this and how do I avoid it in the future? Is it the polyester gelcoat and epoxy resin not liking eachother? Or is it because the epoxy resin kicked during the laminating process? In the future should I try using epoxy just like gel coat? I had this gel coat laying around from an old project so figured I use it to make a good mold.. Thanks in advance!!