Using baking flour as an additive for epoxy

[Ann and Neville Clement]

   We have a cruising friend with extreme low budget and a badly storm damaged wooden dinghy.  He had been given some very old epoxy (the hardener was so dark, it looked like chocolate syrup) and he was desperate for a working dinghy.  Bits of scrap wood was available, tools and a shed was available, so the only thing needed was some courage to use the old epoxy and skill to use the tools.  We decided we had that and our friend had the will to work with us.

    For three days he and Nev fitted replacement parts after removing rot and damage from the elderly two part dinghy.  Another friend works at Wooden Boat and told me we could use baking flour as an additive to thicken it - he had tried it and experimented with it and found it ok.  I had heard that epoxy and hardener are ok many years past the sell by date.  Lacking an alternative, we went ahead and did the glue job today.  The epoxy has gone off properly already, the flour is pleasant to work with, and I suggest you experiment with it for yourselves.  It mixes easily with the epoxy, tools well, and is much more pleasant than wood flour.  Certainly I suggest you never toss out old epoxy.  One always finds these low budget desperate boating friends and it works!

      All the best,  Ann and Nev   

[Geminidawn]

I have heard this before but it is frowned upon for many reasons.

The main solvent in the hardener is ammonia, the more ammonia that evaporates the darker the hardener gets and the less effective it can be, sure you can use old dark hardener but it will never cure as well or as strong as a fresh batch. If I were to still use it, I'd use it only for priming or non structural parts like battery boxes, etc, not to rely on it for keeping me from Davy Jones Locker.

As for the flour it's organic where micro fibers are not, therefore organic materials can break down quicker and leave micro voids in your bond, weakening it. That is why plywood laminates are usually all the same but it is only ever a strong and water proof as the quality of glue that's holding it together.

When it comes to a post incident survey I am often required to send test samples back to a lab to see how and why a bond failed, once any irregularity outside of the resin manufacturers recommendations is found the liability is passed directly on to the builder which could prove expensive and if there was a casuality involved there will be no end to it.

Be it overkill or not that is why home built boats are so tightly regulated here. If it dosen't have a builders plate it has to have 5 years of proven use before it can be re-sold.

 

 

[Ann and Neville Clement]

I understand where you are coming from and appreciate the caution.  But if a man has no dinghy to get to his boat, he is in a desperate situation.  Using the dark hardener to repair the dink (and more than the usual number of screws too) was the only decision reasonable at the time and we were glad to help out. 

 

I was told that the microfibers we bought by the bucket full from West were simply chopped up cotton.  That would be organic.  Also many folks use wood flour which is sanding dust and it would be also organic because of coming from wood that was sanded and the dust saved.   

 

When we built Peace we were unsure how much attention Wharrams had given to the sizes of epoxy fillets in the plans - ours was the Tiki 46 prototype.  When I suggest experimenting with the baking flour, I should be more specific.  Our experiments for the size of fillets were repeated many times during the build whenever we came to a different fillet size.  It consisted of taking scrap ply of the size in use at the time and making the suggested size of fillet we were instructed to use and waiting three days before crushing it in the vise.  If the fillet held and the ply broke, that seemed good enough to me.  But I am not an insurance inspector. 

 

For many folks the cost of West System additives and other additives is prohibitive so the decision is to have a boat or not to have a boat.  There is a lot of money being made by the companies that market the stuff and perhaps some folks can have a dream come true by seeking and experimenting with alternatives.  We did leave our screws in place because we wanted maximum security and we also had our boat surveyed 8 times during the build.  All the screws were embedded in epoxy and were the non magnetic form of stainless steel.  We did this even though we used all West System products and all West System additives and all bought new for the job.  We like to be secure.  If we were to build again (heaven forbid!)  I would do even more experiments with other sources of glue as well as additives.  Perhaps some kind of peel away test could be devised for the home builder and designed for testing bonding strength and other experiments could be devised for other uses of glue.  I know I tested all my fiberlassing the next day by trying to peel it off using pliers and I did need to redo some of the fiberglass work I did.  I was glad to do it so that I could be secure in all the strength of the boat.  Some folks on this site might be interested in sharing information re home testing and other additives.  After all, our professionally built and store bought hatches all do leak but the home built ones from the plans are secure against leaks and several of them do not even have seals.

 

I do agree with the concerns about home builders and the safety issues of amateurs building boats but I have seen some awful examples of "professional boat building" in my life.  Certainly the man who will sail the boat is most interested in its safety or should be.  Because we knew we would be crossing the Atlantic, we were extra careful.  But our friend with the dink that needed repair was only going from the dock to his boat in flat water using oars.  He will not be going to Davy Jones Locker any time soon because of using old epoxy or flour as an additive.  But thanks for the caution.  I do like to be cautious and I do like it when folks on this net are careful.  I deeply appreciate your comments and often read what you write with pleasure.

 

Ann and Nev 

[Geminidawn]

You are right in what you say! I have seen some God awful examples of production boats who's main aim at the end of it all is profit and every job comes down to time and money.

On the other hand, both James and Hanneke have said so themselves and I concur, that there are some homebuilders out there, some even on their first boat, who either due to sheer passion and pride or a desire to do a really good job far exceed professional standards.

But unfortunately EU directives tar everyone with the same brush and here you either fall into one category or the other. There are some "Professional" boat builders that don't deserve the title and some homebuilders that do.

[paul anderson]

i find these posts of great interest especially when the authors have skin in the game,as is the case here keep them coming guys as there are people like me who are building for the first time and would not know to ask some of the questions and answers here.thankyou.

[Ann and Neville Clement]

While we were repairing the very elderly dinghy some more today, we were all so sad to see the poor quality of the ply that was used in its original construction.  I know it is quite elderly, and has been much used and abused over the years, but I keep thinking that if better ply had been used in the first place to build her, she might have stood up better to her hard life.  When working with poor ply, it is hard to keep doing your very best work.  But if the ply is really good, it acts as an inspiration to do the very best job possible and then it is stronger too.  Building mistakes will happen, but the epoxy makes it pretty easy to correct.  We are teaching basic boat building skills to the current owner of the dink and he does have the plans and can someday build a new one.  This wee dinghy is a nesting, sailing, rowing, and (small engine) powering dinghy.  She is not a great beauty because the sheer is just not full of much joy, but she is said to be easy to live with and a pleasure to sail about the anchorage at the end of the day.  So there is justice in saving her.  Also we love the folks who built her and have had her - might be over 20 years old by now. Meanwhile, some folks brought us a sister dinghy in slightly less broken condition and she will be next on the repair list...  Somebody always wants a dinghy around here.  We will fix it and she will be used most likely by visitors on the island.  This second dinghy was almost dropped off at the dump so using our alternate baking flour additive and more of the old chocolate colored hardener will be a better fate for her.  She will live again.  Nev had to grind off some of the glue from yesterday and it was super duper hard.

  

Ann and Nev

   

Ann and Nev

[stephen c veale]

When I built my Tangoroa, Rhiannon, I used cotton sheets epoxied to the douglas fir ply decks.  [instead of fiberglass cloth]  After almost 30 years, there have been no problems that I know of.  The boat has a new owner and I expect him to get many more years of pleasure sailing her.  Good luck builders! 

[Geminidawn]

I guess "necessity is the mother of invention" but if I tried anything like this it would be a career ending move for me!

[stephen c veale]

I assume u r a professional boat builder?  I didn' read your profile; sorry.  I was building the boat for myself so was able to experiment.  some experiments  turned out better than others, but all in, 
they turned out pretty well.  I would like to continue this thred.

cheers,

steve
Geminidawn said:t

I guess "necessity is the mother of invention" but if I tried anything like this it would be a career ending move for me!

[andy solywoda]

I had a bad experience with epoxy glass lamination failing.  The original builder said he had used WEST's own proportional pumps, yet WEST analyzed the samples I sent and said perhaps the epoxy was not mixed to correct proportion.  The repair necessitated stripping the sheathing off a 44 ft hull, refairing it, then resheathing it.  Considering the rest of the original builder's work, I would guess that the problem was more likely in the epoxy or the proportioning pumps. 

This was a lot of work and the prospect of the other hull having the same problem haunts me.  I keep an eye on it. 

Also I found a problem with the cross beams that had absorbed water.  WEST says that their epoxy can get hydroscopic if not mixed correctly.  I was able to use air grinders with rasp bits to excise the soft water laden wood and rebuild the beam. 

 

When we spend so much on materials and our labor and have failure, it ends up a second expense.  Still, enabling a repair on the spot can be very effective, and who knows, I've been told to keep flour out of my diet, what else can I do with it?

 

[Geminidawn]

Even the resin manufacturers don't get it right all the time and I have had a fair few batches that just would not do their job. When this happens and you're on the phone to the complaints department they usually send in a troubleshooter. This may just involve sending them some samples or them visiting your work to factor in your workshop conditions etc. This is why I remain brand loyal and do just what the manufacturers recommend, so if I use "X" brand epoxy I also buy their cloth, microbaloons, colloidal, microfibres, etc. The reason being, once you use a material outside of their technical sheets and your whole job has failed you do not have a leg to stand on.

Personally I don't use any organic compounds if I can help it, flour, wood flour, or cotton fibres as they are all Hydrophilic (high in H2o absorbption) but if it's has the resin manufacturers brand and blessing, no problem as I am passing liability onto them.

andy solywoda said:

I had a bad experience with epoxy glass lamination failing.  The original builder said he had used WEST's own proportional pumps, yet WEST analyzed the samples I sent and said perhaps the epoxy was not mixed to correct proportion.  The repair necessitated stripping the sheathing off a 44 ft hull, refairing it, then resheathing it.  Considering the rest of the original builder's work, I would guess that the problem was more likely in the epoxy or the proportioning pumps. 

This was a lot of work and the prospect of the other hull having the same problem haunts me.  I keep an eye on it. 

Also I found a problem with the cross beams that had absorbed water.  WEST says that their epoxy can get hydroscopic if not mixed correctly.  I was able to use air grinders with rasp bits to excise the soft water laden wood and rebuild the beam. 

 

When we spend so much on materials and our labor and have failure, it ends up a second expense.  Still, enabling a repair on the spot can be very effective, and who knows, I've been told to keep flour out of my diet, what else can I do with it?

 

[Ann and Neville Clement]

   BE EXTRA CAREFUL WHEN EXPERIMENTING!!!    If you intend to do an experiment, start with a little tiny one and wait three days and then test it as best as you can figure out.  If you want to use cotten sheets, then be sure you buy cotten and that it is 100% cotton and not polyester which will not work with epoxy the same way. Then wait three days and try to peel it off.  Try seeing if it matches the strength of fiberlass on some scraps of ply.  Try piercing and peeling etc.

    If you are planning to use flour for additive, then figure out a way to test those bonds.  If it is just a small repair job or your budget is squeaky tight, then perhaps it is worth it to you to make an experiment.  If you are laying the hull of a Tiki 46, as we did, we wanted to be ultra safe and we used all West products to go with all West glue because we were building the foundation for our home.  We did not stray from the highest recommended methods EVER!  During several offshore storms, we were grateful for that.  It gave us comfort!

      I have been trying to come up with some testing that folks might do at home if using flour for bonding and it seems to me if you were to take two pieces of scrap ply and drill holes in one end of each and tie a short piece of strong string through each one of the holes, then you could glue them together flat side to flat side on the ends away from the holes and use a clamp where you put the glue, and after three days see if you can pull the strings and peel the ply pieces apart.  If the ply breaks, that would tell you the bond is stronger than the ply.  It would reassure me.  But hey,  IT IS YOUR BOAT AND YOUR DECISION and Gemini is right when saying that you will be on your own if you stray from the recommended proceedures.  You sure don't want to build yourself a failure and spend all that time and money and energy to make something worthless. 

     Pumps can be your best friends providing accurate measurement, but you should make a test mix from time to time to check that the pumps are working properly.  Again, it is your boat.  We tested and tested while building Peace because I wanted to build us a strong and reliable boat to take us across the ocean.

    Ann and Nev

[stephen c veale]

Chuck, You are correct about using the best materials available.  For my Tangoroa, Rhiannon, I bought the best materials I could find : ie., clear douglas fir timber, marine grade doug. fir plywood, and used  WEST epoxy throughout. I built the first hull in a chicken coop, using a wood stove for heat. 

     However, I made the mistake of using a kerosene tube heater, after rolling a coat  of epoxy on the hull.  The lesson learned was that the hydro-carbons from the heaters exhaust prevented the epoxy from  setting up.  As they say, "time heals all wounds...' but

 ...  I do remember spending alot of time and elbow grease removing the stuff!  Needless the say, that was the last time that heater was used.