vacuum forming

[befu]

Alright, I was asked to show some information about my home vacuum forming setup, so here are some pictures and information that I had posted in the 18.5" mystic build thread.

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My vac table is at work, so i should be able to post pictures tomorrow.

I use two - 2 stage vacuums in series which gets me a little over 10 inches of mercury, actually about .35 Atm. together they pull about 17 amps. I use a vacuum pump and a 3 gallon storage tank for secondary vacuum using a modified sump pump valve. the pump only goes to 20" mercury and the 3 gallons is not enough volume, so I need to work on that.

the table has a series of 1/2" holes for the vacuum to come through in about a 2" by 6" area. The table size is about 20" x 15", but can be changed by placing a platen on top of that. For the 23" x 16" frames I am using right now, I use a piece of 1/4" pegboard that is about 21.5" x 14.5" as the platen. It has foam around the bottom to seal it to the main table. makes it very adaptable to other sizes.

My frames are made from 1/2" aluminum angle.

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[D&D]

Being and old nitro boater used to all of my electronics being inside a radio box, my mind searches for ways to more eaisly water-proff the inside of the hull. For example, I have a Aeromarine Mean Machine which is noted as having a difficult hatch to tape. I was wondering if you thought it might be feasible to vacuform a "thin" subhatch that would fit under the normal hatch and could be taped along the inside ridge of the hatch opening. I think I have seen this on some boats, but wondered if you thought that would be difficult on the MM, maybe using the original hatch as the form?

Dennis (D&D)

[befu]

Yes, that would be possible.

Solutions to the mean machine is particular: (I have one)

First, my solution. Make it slow enough that it does not need a taped hatch. I put a thin soft foam around the lip of mine, dowels in the front of the hatch to hold it down and a thumb screw to hold the back down. Works really well to keep water out, but would not be water proof if it flipped.

Second, buy a new style hatch from OSE for the $35 which is easy to tape down.

Third, vacuum form a piece of plastic and tape it down to the lip as you suggest. You could use Pet-g as it would be clear. That way you can mount the lid as the first solution and it goes on and off really easy. When you pull the lid, you can see the insides right away to see GPS units, voltage monitors, or if thier is any water in it. It wouldn't have to be super strong either as the main cover would take the impact.

As far as shape, it would just have to be smaller than the outer hatch and still clear any thing that would stick up above the hatch lip inside the boat. Pretty much just the motor and mount.

So, yes this is possilbe. McMaster has Pet-g in 1/16 which is pretty heavy for about $2.50 a sq ft delivered. I would only get two pieces out of a 24" x 24" piece, so raw material is about $5, if I don't screw anything up! If I use HIPS, it would be solid white but cheaper. I don't know, you want me to try one for you? I think $10 - $15 would cover the plaster cast, plastic and shipping. Not making a profit, just offering the service if you are interested.

Brian

[D&D]

Brian,

First, being that old nitro racer that slow is not an option. Second, while I have not began my MM build I already have a New 1515.1Y and I don't think I could made it slow.

Your second suggestion I am already looking into. I have corresponded to Bob who makes the alternate MM hatch and am waiting for Aeromarine to send me a color example to ship him.

Your third, suggestion; "Vacuum form a piece of plastic and tape it down to the lip as you suggest," seems like it could be a good idea for many different boats. Also using the Pet-g (clear) would be great, but some sort of a "lip" would be required to allow for taping. Also as you stated, it would have to be smaller than the original hatch to allow the original hatch to fit the hull properly. Would that be light, but still stiff enough not to sag into the hull?

Another advantage of your 3rd suggestion is that I know, from past experience, that Aeromarine's hatches also take into consideration the aerodymanics of the hull. Although I am interested in Bob's alternate MM hatch, I am concerned that all of the flat surface might act as a wing and provide lift to the hull. Cat boats have enough lift in the tunnel.....

Thanks for your offer to help and I may check back with you and ask for your assistance later, but for now let me keep thinking about this.

Dennis

[wolf IV]

man you guys are hitting on exactly what i was thinking for my soon to be three hydro builds !!! this is a great idea!! although without all the equipment i may just foam shape and tool up my subhatches via epoxy/cloth...:( this would be soooo much easier.. youve got a great machine there!!!

[Mono~Junkie]

Nice Vac set-up!

I have been putting one together, nothing fancy but i want to keep tinkering with hull improvments and want to form each change to compare results.

where is the best place to get the abs though? I have been googling, but think I am finding all the industrial sites that just seem so abstract in their ordering amounts.

Any advice would be great,

thanks,

Kyle

( Edit )

Maybe I should also state that the hulls I am working on are 26 x 9 so if that helps any in being able to point me in a direction that can offer sizes of this nature.

Thanks,

[Jeff Wohlt]

You really want HIPS (high impact polystyrene) Stronger and easier to form.

Mine has one hole in the center of the board. if you go check out k560 site you will see that most are going with one hole...no box so basically mine is a board with a shopvac coupler hooked to a 6hp craftsman shopvac. You can always use a secondary tank once you pull it down with the shop vac for that extra power...let the shop vac pull it down then open the valve to your tank...you use very little from the tank when doing this way.

Buy big sheets and cut them to your specs and frame size...cheaper that way.

[wolf IV]

How are these plates of styreene heated, and to what degree? Also is it possible to heat the hips plate to a poiint where it will almost just lay/sag over a plug? The plug would just be a mock of the hull opening w/ protruding motor which is preventing just a flat plate inst. Whats the thickness recommended 1/16 or 1/32"? In other words is it possible to form the heated hips w/out vacuum forming just for this application?

[D&D]

Making a plug, as you stated, sounds like a good idea! A raised portion for the protrusions (motor, etc.) and then the remainder a nice flat fit for the remainder of the hatch opening. Here's another suggestion, make the plug with a crevis near the edge to allow the styreene to sink down into (about a quarter-inch). This would create an "edge" that would just fit down into the hatch opening thereby "holding" the hatch opening "cover" in place for proper taping........

[Jeff Wohlt]

Nope...you really have to get it just right for pulling. Too soft and she will leave bad corners and to hard and it will not pull.

Takes testing...I pull .062 and it has to be just right.

Molds are easy depending how many pull you want from it. You can even pull over a FG object if you want.

[wolf IV]

Nope...you really have to get it just right for pulling. Too soft and she will leave bad corners and to hard and it will not pull.

Takes testing...I pull .062 and it has to be just right.

Molds are easy depending how many pull you want from it. You can even pull over a FG object if you want.

well shoot!! it might be worth just drilling a single hole in the cowl and pulling it strait into the cowl !!! in other words using the cowl for the mold.. this would make the sub hatch a perfect fit..

[befu]

Making a plug, as you stated, sounds like a good idea! A raised portion for the protrusions (motor, etc.) and then the remainder a nice flat fit for the remainder of the hatch opening. Here's another suggestion, make the plug with a crevis near the edge to allow the styreene to sink down into (about a quarter-inch). This would create an "edge" that would just fit down into the hatch opening thereby "holding" the hatch opening "cover" in place for proper taping........

That is a good idea on the recessed lip, only problem I see with it is all the hulls are not trimmed out equally. All depends on how the hull opening was trimmed.

Brian

[D&D]

Brian,

I was thinking of a custom plug for my hull, you took the idea much farther - a plug, for example, that work for all Mean Machines....

I still think there is a good idea here that would simplfy the water proofing of a hull.

Dennis