The Mold Part 2

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Canoe Project Home - The Strongback - The Form - The Mold (part 1) - The Mold (part 2)
The Layup (part1) - The Layup (part 2) - The Layup (part 3) - Project Finish (gunwales) - Project Finish (floats) - Project Finish (seats)

The Rebuild Part 1
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   I used some thicker clumps of the old drywall compound in a attempt to fix the bow and stern profile. This at least filled in the gaps where the foam did not come to a V on the profiles, however I suspect this will give me more work later. 
   I bought a new bucket of pre-mixed drywall compound, what a difference. This was thick and fluffy as (if you could call drywall compound 'fluffy'). I had the look of Marshmallow Fluff yet not the lightness. I hope final canoe will weigh less than the bucket of drywall compound (62 lbs). I used almost the entire bucket on the first layer of compound over the foam.  I kept a little aside to use on the bow and stern profiles when the first coat dries. It may be a couple of days until I can work on the mold again due to expected rain.
   08-13-2005 - The rain came, thus I covered the mold with a tarp. It took thee days for the first coat of drywall compound to dry.  As per the recommendation of the of the book for the second coat I purchase a bag of powered drywall compound.  I noticed a brand called durabond which claimed to set hard like plaster. In my haste to get out of the store and back to work on the canoe mold I grabbed a bag which sets in 20 minutes. I had intended on purchasing a compound which set up in 45 minutes.  The 20 minute variety set up to fast, however it was great to fix bow profile.
   08-14-2005 - Having learned another lesson (the joint compound takes a long time to dry when covered with a tarp in the rain) I used parts of an old carport to make a structure that would cover the mold yet keep the tarp from touching it.  With the 20 minute set time of the durabond too fast I purchased a bucket of 'light joint compound'. This was billed as having less shrinkage and bring more easy to sand than general purpose joint compound. It did a fine job filling the cracks which developed as the first layer of compound dried and covering the mold.  I am concerned that it may be to fragile to use as the as a final coat..
   While trying to refine the stern profile shape I noticed that the there were cracks and that it was still soft. I then scraped off the first layer of compound and started new with the durabond, it worked great. Having been out of state and stalled do to rain delays I used the most bucket of the lightweight drywall compound for the the second layer on the mold and the rest to fill some low spots.  Having run out of the pre-mixed compound I went back to the duarbond, this caused me more work because it set so quick.  
   08-24-2005 -  I then I purchased a third bucket of pre-mixed compound to work on the third layer which was a lot of fill. Sure the drywall compound helps to cover (no pun intended) some of the errors which I have made in the previous steps, it however takes a large amount of compound. J I still have some areas which are need fill and some areas which were filled too much, all of this requires sanding. A word of caution here: wait until the joint compound is fully dry before you start to sand it or you will end up with more filling and sanding - oops again.
   08-25-2005 - I had the 'bright' idea today to use the surform plane to remove the uneven spots in the mold, it worked great . . . except it also left grooves in places which need to be sanded our or filled. Today we sanded the mold some more. Of course the children became quickly board with doing actual work and left it for me. I did get myself into this project. There will be a lot more sanding that needs to be done before the wax is applied and I will need to add some more compound in places.
   To assist my effort in applying the layers drywall compound I have purchased a 12 inch tape  knife used to smooth a larger area.  It has worked well (will wonders never cease, I made a choice which did not make more work). I apply the compound with the 6 inch knife and smooth it with the 12 inch. With the 12 inch knife I do not make as many groves which will need to be sanded.  That is not to say I eliminate them, I am not much better with finish work with the joint compound than I am with the jigsaw. Truth be told I am a little better with the forgiving compound.
   A word of note: It would be helpful to have an air compressor handy to remove the dust from sanding off the mold before adding layers of compound.  I do not have one thus used a paint brush to brush off the dust (from sanding) and it was not entirely effective. As I added layers of compound the remaining dust inhibits the wet compound from sticking to the mold until I worked it (the dust I failed to remove) into the wet compound.  Another lesson learned.
   08-27-2005 - The forecast calls for thunderstorms until late afternoon, the sun came out. I removed the dust (from sanding the last coat) with a paintbrush. Anxious to finish the mold started with the third full coat of drywall compound. I started to fill the rough spots on the mold and the groves caused by over zealous use of surform plane. I also had to fill some cracking of the compound.
   While I was working on the this the 'final' layer of joint compound it started to rain. by the time I got the tarps over the mold the rain had stopped and I had done more damage to the wet compound with the tarps. I needed yet another bucket of pre-mixed compound, the fourth. I believe this will is to be the final finish coat and will only need a little touchup after sanding to fill any voids left.
I also purchased some tack cloth to help remove the dust.
Today I completed the order for the Kevlar/Carbon fiber and S-Glass cloth from which the canoe will be made. I Plan on using two layers of the hybrid cloth in hope that it will help to minimize the use reinforcing ribs needed. The book calls for one layer of Kevlar. 
  08-31-2005 - My third and 'last' layer wasn't. I found that it was more easy to cover voids with a thick layer of compound, thus making more (yet smaller voids). I was as yet unhappy with the symmetry of the mold where I could see low spots. These were filled with very thick layers of compound which when overfilled needed to be sanded quite a lot. Today I hit upon the idea of wetting my sanding sponge (by need to clean it and at suggestion of my brother) which made smoothing out high spots much easier. I sanded the entire mold several times. I used the last of the third bucket of drywall compound to fill in in any low areas on the mold that could be felt but not necessarily seen. I hope to finish sanding tomorrow and start applying the melted paraffin wax.
  09-04-2005 - Got back to work on the project toady after a break do to another project. I used some tin purchased at the local dollar store to construct a double boiler. The heat source was a disposable camping burner.
  I placed a larger tin over the bottom boiler tin (which contains the heat source) and put water in it (hence the double boiler).
  I melted the wax in a stainless steel bowl (purchased at the same dollar store as about at the same time).
  I started to apply the wax with a paint roller (this picture was taken with a timer since I was alone). The book says to start from the gunwale and push the wax ahead of the roller only in an upward direction. The one (and only) illustration in the book makes this look like a simple process where the wax will start to drip and will need to be caught with paint pan so as not to have it drip on the floor. I found that the wax solidified very quickly upon application and notice what I took to be a problem almost immediately.
  The first problem was that the wax started to peel away from the smooth surface mold anywhere it was to thinly applied. Maybe I sanded the mold too smooth, thought I.
The second problem was that I quickly ran out of melted wax thus needed to set up another double boiler or wait twenty minutes for wax to melt between applications.
  I had both boilers melting wax and tried to clean tools of it while waiting for more to melt. I found that the wax was setting too fast for effective coverage using only a paint roller thus also used some foam paint brushes to assist in the chore. I had quite a mess left when finished. Most of the items I used for the wax application where inexpensive dollar store items which will be discarded.
  After about four hours I had used my entire supply of wax (eight pounds) and the mold was covered with a thick coat. This was not an smooth and even coat of wax, this will be fixed by re-heating the wax with a heat gun or old clothes iron. The job of applying the wax done and me not being able to find the old cloths iron I intended to use to re-melt the wax I was finished for the day.
  In the one picture in the book of wax being applied the coat did not look anything like the surface of my mold when I had finished. My mold was very bumpy and uneven. I can only hope that the re-melt will fix this.  There seems to be a reoccurring theme with my hope that the next step in the process will fix the errors of the current step. If I should run into such troubles when doing the layup there will be no next step which will fix errors, as I have stated before this will be a unique boat.
  09-05-2005 - I started to re-melt the wax with an old cloth iron (as per suggestion in the book) it worked to melt the wax, however with the cured hull I found it to be not very effective and left lines of melted wax.
   I purchased a heat gun to re-melt the wax and used a plastic putty knife to scrape the excess off. It took me over two days to remove the wax. Removing the excess wax was a lot more work than applying it.
  Here is the picture of the waxed mold. I do not see the point of applying the wax in the first place. It seem some places the wax just seemed to evaporate and left the mold unchanged in other locations it discolored the mold. There were plenty places where I gouged the underlying mold in trying to scrape it.
  09-06-2005 - Even though the book does not call for this the step of sanding the waxed mold I did so regardless using only a drywall compound sanding screen. My goal was to fix the defects caused when removing the wax. I did not sand to the underlying compound just the wax surface. Wanting to get this project back on track I started to apply the mold release wax and buffing it out after each coat. This picture is of the mold in the finished state from bow to stern.
  The finished mold (with mold release wax).
  I applied the entire 24oz. container of mold release wax (Partall from in seven coats of the next two days. I buffed the mold by hand after each coat. I was happy with the mold before the wax (paraffin) step, less so after it. I have decided that any small anomalies in the shape of the mold will have to stand.  This will be a unique boat.

The next step to to start the layup.
  Previous: The Mold Next: The Layup (part1)
Canoe Project Home - The Strongback - The Form - The Mold (part 1) - The Mold (part 2)
The Layup (part1) - The Layup (part 2) - The Layup (part 3) - Project Finish (gunwales) - Project Finish (floats) - Project Finish (seats)

The Rebuild Part 1