[PSUBS-MAILIST] R300 FRP work

Fri May 22 13:10:36 EDT 2015

Sean, I am scheduled to be in Perth Australia that week.  I am teaching an oil and gas engineering short course.  Having said that  with the oil price down this session may not make.  I won't know for a while.  If the class does not make, you are surely welcome to come for a visit.  I have a spare bedroom we cold put you up in.  

Let's chat in a month or so.

Best regards

Cliff

Cliff Redus

> On May 22, 2015, at 11:54 AM, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Cliff, I'm on conference in Austin for August 2-7.  If by any chance you and your boat are going to be home at that time or the following weekend, I could probably manage a side trip to Devine to have a chat if you're available?
> 
> Sean
> 
> 
>> On May 22, 2015 10:19:33 AM MDT, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> Sean, good to hear from you.  I am waiting to get on a plane to Barcelona so this will be brief.
>> 
>> From what I understand of the photos, you design the hydrodynamic
>> fairing and then create virtual slices of the completed design, which
>> you fabricate out of expanded polystyrene.  I presume the slice
>> thickness just depends on the available thickness of polystyrene board
>> 
>> Yes, I used 4'x8' x4" sheets.
>> 
>> and/or how much work you want to do in shaping?  I notice that you have
>> these sections joined with wire ties in the photos... am I correct in
>> assuming that this was a temporary measure, and that you moved to
>> adhesives etc. prior to the body filler?
>> 
>> Yes, used a special spray on adhesive that joined the sections.  I used a CNC flat bed cutter that a local furniture fabrication company had to cut the section profiles based on a Autodcad drawing of the sections.  Bailing wire was used to temporary hold the sections until the adhesive set.
>> 
>> 
>> Once you've carved the EPS down to shape, you cover in a layer of body
>> filler which you can further refine and sand to a smooth finish, which
>> you then painted.  Is the paint necessary?  Or can you j! ust apply a mold
>> release at that point?
>> 
>> Paint is probably not necessary but I wanted to make sure the mold release worked correctly.
>> 
>> After that, it would appear that you added flanges to define the mold
>> split lines.  Were these centered on the split line, or did you move
>> them slightly before laying up each half? 
>> 
>> Slightly off-center so that face was on centerline plane,
>> 
>> Furthermore, was it necessary
>> to split left and right, or do you think you could have done the mold as
>> only two parts?
>> 
>> Not sure I could have removed the female mold from the plug mold without splitting down the middle.  Also it made it easier to do FRP layup on the haves.
>> 
>> Do you just use a mold release on the plug and then start fiberglassing,
>> or do you apply a gelcoat first?
>> 
>> I used a mold release on the plug first.
>> 
>> Did you lay up the whole mold at once and then cut at the flange, or did
>> you do a section at a time?
>> 
>> Section at a time.
>> 
>> Once the female mold was finished, I presume you did some further
>> finishing / smoothing to the inside surface?
>> 
>> Yes, even though I sprayed a gel coat the surface was not clean enough so used normal auto paint procedure to paint the FRP shell.
>> 
>> Then a mold release / gel coat / glass to create the shell?
>> 
>> Yes
>> 
>> Once the shell was done and trimmed, how did you join the pieces
>> together and smooth the seam before casting your syntactic in?
>> 
>> Assembled on the pressure hull and used normal FRP layup techniques to join sections.  This normally included grinding down the joints and doing a layup.  
>> 
>> Om my next boat I am looking at generating a polystyrene plug mold 
>> cut on a 3-d CNC machine.  I would then apply tin foil to plug and lay the final FRP! shell on this.  This will give better dimensional shape and should be quicker.
>> 
>> Got to run.
>> 
>> 
>> Cliff Redus
>> Redus Engineering
>> USA mobile:  830-931-1280
>> cliffordredus at sbcglobal.com
>> 
>> From: Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org>
>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>> Sent: Friday, May 22, 2015 10:28 AM
>> Subject: [PSUBS-MAILIST] R300 FRP work
>> 
>> Cliff - I have once again been studying your photos of the R300 build,
>> and I was hoping you might be able to elaborate a bit on the process you
>> used to construct the FRP fairing.  There are a couple of details that I
>> am still fuzzy on...
>> 
>> From what I understand of the photos, you design the hydrodynamic
>> fairing and then create virtual slices of the completed design, which
>> you fabricate out of expanded polystyrene. !  ; I presume the slice
>> thickness just depends on the available thickness of polystyrene board
>> and/or how much work you want to do in shaping?  I notice that you have
>> these sections joined with wire ties in the photos... am I correct in
>> assuming that this was a temporary measure, and that you moved to
>> adhesives etc. prior to the body filler?
>> 
>> Once you've carved the EPS down to shape, you cover in a layer of body
>> filler which you can further refine and sand to a smooth finish, which
>> you then painted.  Is the paint necessary?  Or can you just apply a mold
>> release at that point?
>> 
>> After that, it would appear that you added flanges to define the mold
>> split lines.  Were these centered on the split line, or did you move
>> them slightly before laying up each half?  Furthermore, was it necessary
>> to split left and right, or do you think you could have done the mold as
>> only two parts?
>> ! 
>> Do you just use a mold release on the plug and then start fiberglassing,
>> or do you apply a gelcoat first?
>> 
>> Did you lay up the whole mold at once and then cut at the flange, or did
>> you do a section at a time?
>> 
>> Once the female mold was finished, I presume you did some further
>> finishing / smoothing to the inside surface?
>> 
>> Then a mold release / gel coat / glass to create the shell?
>> 
>> Once the shell was done and trimmed, how did you join the pieces
>> together and smooth the seam before casting your syntactic in?
>> 
>> Thanks in advance.
>> 
>> Sean
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>> 
>> 
>> 
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