Nidacore Test

Discussion in 'Fiberglass and Composite Boat Building' started by reelpleasure, May 25, 2013.

  1. reelpleasure
    Joined: Feb 2013
    Posts: 27
    Likes: 1, Points: 0, Legacy Rep: 12
    Location: Massachusetts USA

    reelpleasure Junior Member

    Hello all,

    I have 2 or 3 questions.


    This is my "1st time" fiber glassing and I'm doing some testing of my skills or lack of finishing some panels with glass and gel coat ect.

    I "wetted" the Nidacore and then laid 1.5 oz mat over the Nidacore wetting and rolling in the mat.

    This 24X50 inch piece with 1 layer of 1.5 oz mat used 1 qt. of resin. Sound about right ???

    Tomorrow I will lay another layer of 1.5 oz mat on this one. Question, will I have to "grind or scuff" the 1st layer of hardened mat or can I wet out and apply another layer wetting through the new layer?

    The opposite side of the Nidacore I plan to wet out a layer of 1708 and then immediate "hot coat" a layer of 1.5 oz mat over the 1708 ? Is this "OK" to do or will the double layers result in "bubbles" weak spots or "whatever" ?

    Finally, If I do the layer of 1708 AND the 1.5 oz mat over it do I keep the "20 min mix rate @ 1 teaspoon of catalyst to 1 qt. of resin??

    Appreciated, Bill D
     

    Attached Files:

  2. tunnels

    tunnels Previous Member

    testing ?? you must be kidding !!

    one tea spoon of catalyst!! you have to be accurate than that ,that is real slap dash and back yard stuff !! how do you know what ratio /percentage you using ?? the resin maybe never reaching its true potential hardness and as for making hot brews, forget it , adding to much catalyst is as bad as not enough and makes it hard ok but to the point of becoming brittle and if you keep going reverts to being like rubber till eventually you drown it and its just filling for the rubbish bin !!

    There nothing wrong with nida core !, just a 1.5 oz of glass is not very strong by its self, the 1708 is what gives the strength why don't you put the two on together and roll it out to get rid of the air bubbles !! you should be aiming for about 25 to 35 minutes the get gel time from your resin which is usually 1.2 to1.5 % of catalyst at around 22c temperature !not forgetting 70% of humidity !! yes they both change the way the resin reacts !!.
    Best don't guess be accurate with the weight of the resin and the measuring of the catalyst and know what the gel time is you getting so you know how long you have to work with it !!
    All resin have there limitations of hardener mixes no mater what they are !! if you cock it up then its your fault don't blame the products!!. 90 % of failures are because of poor workmanship[ and not understanding the materials you using ! 10 % is bad choice of materials . :(

    My point is if you don't start off like you mean to carry on you will get no where !! you end up with false answers and nothing works properly !!
    Do the job properly and you will end up with more help than you can cope with . BUT if you continue on the slap dash she'll be right mate then that's all you will ever know and be missing out on so much !!! already had one young guy here didn't do things properly and cost him his mould and a boat !!
     
  3. reelpleasure
    Joined: Feb 2013
    Posts: 27
    Likes: 1, Points: 0, Legacy Rep: 12
    Location: Massachusetts USA

    reelpleasure Junior Member

    I read the labels !!

    Tunnels,

    I read the labels and used a "measuring cup" for the catalyst.

    I appreciate your feedback.

    Thank you,

    Reelpleasure
     

  4. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 197, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

    You need 1 to 2% catalyst to resin ratio for a good cure. Depending on temperature and/or how fast you want it to be workable, you can vary the amounts. A quart is 192 teaspoons, so with 1 tsp, you are mixing at about a 1/2% ratio. 2 tsp will be about 1%, 3 will be about 1 1/2% and 4 will be about 2%.

    Go here and click on the chart to make it readable.

    http://www.boatdesign.net/forums/fiberglass-composite-boat-building/fiberglass-thickness-8686.html

    Where I penciled in ' 9# ' means that is about the weight in lbs of 1 gallon of polyester resin.

    You did about 8 sq ft of 1.5 oz mat, which takes about .219 lbs of resin per sq ft. So 8 x .219 equals 1.75 lbs. Since one qt of resin weighs about 2.25 lbs, you put 1/2 lb too much on there. BUT, the chart isn't taking in to account absorption of resin by the substrate (the nida core) so you probably didn't do too bad for a first try. A little too much resin is better than too little.

    You ask simple questions but the answers aren't that simple.

    If you used laminating (unwaxed) resin, you would only need to scrape off any lumps or hardened threads that will keep the new glass from laying flat. If you used finish (waxed) resin, you will have to remove the wax by grinding and washing with a solvent.

    The two layers could have been applied one right after another, which would have eliminated any cleanup work and allowed you to do side 2 today, instead of preparing and finishing side one.

    For side 2, if temperatures are reasonable, you can mix a 1% or 1.5% batch and do it all at one time.

    A good bubble buster roller will help you a lot in eliminating bubbles and consolidating the laminations. It also leaves a better looking, more uniform laminate with fewer lumps, snags, loose threads etc that have to be cleaned up by sanding or grinding. It will also help in using the right amount of resin, as excess resin will become apparent and can be cleaned off before it sets. A metal bb roller is best, as when it plugs up it can be set on fire with a torch and all the hardened resin burned off, which is the only practical way to get it off.

    Sanding and grinding is not enjoyable, a sharpened paint scraper is faster and will eliminate S & G dust, therefore a lot of the itching and mess of S & G.

    Mat weights are always stated in ozs per sq ft, while fabrics are always stated in ozs per sq yd. The 1.5 oz mat is actually 13.5 oz per sq yd. The 1708 means a 17 oz per sq yard fabric with a .8 oz per sq ft (or 7.2 oz per sq yd) mat. In the chart, if you use the numbers for 3/4 oz mat and 18oz WR, you'll come close to the resin requirements for the 1708.
     
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