The present invention relates to a method for pro- ducing laminated objects, such as boats, of plastic, ac¬ cording to which method a frame is produced, the surface of the frame is roughly smoothed, the surface is provided with a smoothing layer accomplishing the final smoothing, the smoothing layer is provided with a layer which ensures the releasing of the laminate, the laminate is placed on the release layer and when the laminate has hardened it is detached from the release layer. The invention also re¬ lates to a frame for producing laminated object of plastic. When producing notmass-produced objects as, for example, boats of laminated plastic one usually starts by making a so called frame which in boat building reminds of a wooden boat. Thus the frame is provided with ribs to which a cover of boards or, for example, plywood plates is fastened. In order for the frame to be suitable to use as a base for the laminate its surface must be made very smooth and be provided with a layer which makes it pos¬ sible to separate the frame from the laminate when the laminate has hardened.

In order to smooth the surface of the frame it is known to plane the boards and then place one or two fibre- glass sheetings and a layer of hardenable, fluid plastic on the cover of boards or plates. The remaining irregula¬ rities are removed by filling, whereafter the dry surface is ground and painted in order to achieve a hard and smooth surface. To this surface several layers of wax are applied, which ensure that the laminate will not fasten on the frame. Some times it is considered necessary to cover the outer¬ most layer of wax with a release film consisting of a vo¬ latile alcohol. When the frame has been produced a wished number

of fibre-glass sheetings and fluid plastic is placed on the surface of the frame and when the laminate has hard¬ ened the frame is disattached from the laminate consti¬ tuting the boat. Finally the surface of the laminate is painted.

On the basis of the above description it is evident that the producing of the frame is very laborious which leads to high production costs. Hereby, for example, every layer of wax must be allowed to dry for at least four hours before the next layer may be applied. In addition, the surface of each layer must be polished.

The object of the present invention is to provide a method which considerably simplifies the producing of laminated objects by means of a frame. The method accord- ing to the invention is characterized in that as the smoothening and release layer a PVC film without softener is placed on the surface of the frame.

According to the invention it has surprisingly been discovered that all the work phases directed towards achieving smoothing and release layers on the frame can be replaced with only one work phase comprising the place¬ ment of a PVC film without a softener on the surface of the frame. In practical tests it has turned out that the PVC film gives the frame a sufficiently smooth surface if the board cover of the frame has been planed before the applying of the film and that the PVC film does not attach to the laminate. Thus the frame can be produced in a much shorter time than earlier, which naturally lowers the production costs of the object. The thickness of the PVC film depends on the smooth¬ ness of the frame in that on an uneven base a thicker film is used than a smooth frame. Suitable film thicknesses are 0,10 to 0,50 mm, preferably about 0,30 mm.

Since the film does not contain any softener it is a so called hard film having a certain rigidity. Because

of this the film often has to be warmed up when it is applied to curved or vaulted surfaces on the frame.

The present invention relates also to a frame for producing laminated objects, such as boats, of plastic, consisting of a body, the surface of which is provided with smoothening and release layers. The frame according to the invention is characterized in that the smoothening and release layers consist of a PVC film without softener. The invention will be described in detail in the following under reference to the enclosed drawing showing a section of a boat frame as a principle view.

The drawing shows a frame for producing a hull of a boat. The frame consists of ribs 1 which are transverse with respect to the hull and on which longitudinal boards 2 are attached. The drawing also shows a PVC film 3 on the outer surface of the boards and a laminate 4 on the outer side of the film, which laminate constitutes the hull of the boat. In order to make the figure clearer the boards 2, the film 3 and the laminate 4 are drawn spaced apart though they in fact bear against each other.

When the wooden frame has been produced the outer surface of the boards 2 is planed so that the surface of the frame becomes essentially smooth.

According to the invention a PVC film 3 which does not contain any softener is applied to the outer surface of the boards 2. The film must not contain any softener, because this would react with the fluid plastic in the laminate 4. A suitable film is the ML film produced by Oy Wiik & Hδglund Ab which is available in thicknesses from 0,12 to 0,50 mm. If the outer surface of the boards is smooth it is possible to use a thin film whereas an uneven board surface requires a thicker film.

In some cases it is possible for the film to lay loosely on the boards, but in most cases it is necessary to attach it to the board surface by means of, for example.

a fixing agent, staples or tape. If the plastic film cannot be made to bear evenly against the outer surface of the boards the film may be warmed up at the location, whereby it will fit to the shape of the structure. The PVC film is in the shape of, for example, 500 mm wide strips which are applied adjacent to each other.

When the PVC film 3 has been placed on the outer surface of the frame the laminate 4 is applied to the frame in a customary way. The laminate consists of fibre- glass sheetings which are soaked in fluid plastic. When the laminate has hardened it can be removed from the frame whereby the film 3 will remain on the boards.

The inside of the laminate 4 may be coloured in connection with the lamination if the film 3 is coated with a dye before the lamination. In this case, however, a certain fastening effect is created between the film and the laminate and therefore the film must be warmed up when the laminate is detached from the frame.

The method according to the invention is also very useful when producing ditches with a rounded bottom. Such ditches are used on boat decks to lead away water. It is known to shape the ditches of boards so that they get a square cross section, after which the corners at the bottom of the ditch are rounded with the help of putty. Finally the laminate is placed on the surface of wood and putty.

The rounding of a ditch may now be carried out in a much simpler way by placing a PVC film in the ditch and fastening it to the longitudinal edges of the ditch.

The invention has above been described in connection with the producing of a plastic boat but the method and frame according to the invention can, obviously, be used also in the production of other laminated objects as, for example, different kinds of casings and covers for the in¬ dustry.